Merge remote-tracking branch 'origin/5.15' into dev

Change-Id: Iaac26eb3c356beb28f70417d63fd00bd0efb57ee

33 files changed, 1742 insertions, 736 deletions

diff --git a/src/assistant/assistant/assistant.pro b/src/assistant/assistant/assistant.pro
index b63be28c7..5da0b0077 100644
--- a/src/assistant/assistant/assistant.pro
+++ b/src/assistant/assistant/assistant.pro
@@ -23,14 +23,14 @@ HEADERS += aboutdialog.h \
     cmdlineparser.h \
     contentwindow.h \
     findwidget.h \
-    filternamedialog.h \
+    helpdocsettings.h \
+    helpdocsettingswidget.h \
     helpenginewrapper.h \
     helpbrowsersupport.h \
     helpviewer.h \
     helpviewer_p.h \
     indexwindow.h \
     mainwindow.h \
-    optionswidget.h \
     preferencesdialog.h \
     qtdocinstaller.h \
     remotecontrol.h \
@@ -56,14 +56,14 @@ SOURCES += aboutdialog.cpp \
     cmdlineparser.cpp \
     contentwindow.cpp \
     findwidget.cpp \
-    filternamedialog.cpp \
+    helpdocsettings.cpp \
+    helpdocsettingswidget.cpp \
     helpenginewrapper.cpp \
     helpbrowsersupport.cpp \
     helpviewer.cpp \
     indexwindow.cpp \
     main.cpp \
     mainwindow.cpp \
-    optionswidget.cpp \
     preferencesdialog.cpp \
     qtdocinstaller.cpp \
     remotecontrol.cpp \
@@ -97,7 +97,7 @@ win32 {
 FORMS += bookmarkdialog.ui \
     bookmarkmanagerwidget.ui \
     bookmarkwidget.ui \
-    filternamedialog.ui \
+    helpdocsettingswidget.ui \
     preferencesdialog.ui \
     topicchooser.ui
 
diff --git a/src/assistant/assistant/assistant.qch b/src/assistant/assistant/assistant.qch
index fded08e62..b58b7ecca 100644
--- a/src/assistant/assistant/assistant.qch
+++ b/src/assistant/assistant/assistant.qch
diff --git a/src/assistant/assistant/assistant_images.qrc b/src/assistant/assistant/assistant_images.qrc
index e55b6b27e..948de970f 100644
--- a/src/assistant/assistant/assistant_images.qrc
+++ b/src/assistant/assistant/assistant_images.qrc
@@ -10,9 +10,7 @@
         <file>images/mac/editcopy.png</file>
         <file>images/mac/find.png</file>
         <file>images/mac/home.png</file>
-        <file>images/mac/minus.png</file>
         <file>images/mac/next.png</file>
-        <file>images/mac/plus.png</file>
         <file>images/mac/previous.png</file>
         <file>images/mac/print.png</file>
         <file>images/mac/synctoc.png</file>
@@ -25,9 +23,7 @@
         <file>images/win/editcopy.png</file>
         <file>images/win/find.png</file>
         <file>images/win/home.png</file>
-        <file>images/win/minus.png</file>
         <file>images/win/next.png</file>
-        <file>images/win/plus.png</file>
         <file>images/win/previous.png</file>
         <file>images/win/print.png</file>
         <file>images/win/synctoc.png</file>
diff --git a/src/assistant/assistant/helpdocsettings.cpp b/src/assistant/assistant/helpdocsettings.cpp
new file mode 100644
index 000000000..dc4afdb86
--- /dev/null
+++ b/src/assistant/assistant/helpdocsettings.cpp
@@ -0,0 +1,231 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "helpdocsettings.h"
+
+#include <QtHelp/QCompressedHelpInfo>
+#include <QtHelp/QHelpEngineCore>
+#include <QtHelp/QHelpFilterEngine>
+
+#include <QtCore/QVersionNumber>
+
+#include <QtDebug>
+
+QT_BEGIN_NAMESPACE
+
+class HelpDocSettingsPrivate : public QSharedData
+{
+public:
+    HelpDocSettingsPrivate() = default;
+    HelpDocSettingsPrivate(const HelpDocSettingsPrivate &other) = default;
+    ~HelpDocSettingsPrivate() = default;
+
+    QMap<QString, QString>            m_namespaceToComponent;
+    QMap<QString, QStringList>        m_componentToNamespace;
+
+    QMap<QString, QVersionNumber>     m_namespaceToVersion;
+    QMap<QVersionNumber, QStringList> m_versionToNamespace;
+
+    QMap<QString, QString>            m_namespaceToFileName;
+    QMap<QString, QString>            m_fileNameToNamespace;
+};
+
+
+HelpDocSettings::HelpDocSettings()
+    : d(new HelpDocSettingsPrivate)
+{
+}
+
+HelpDocSettings::HelpDocSettings(const HelpDocSettings &) = default;
+
+HelpDocSettings::HelpDocSettings(HelpDocSettings &&) = default;
+
+HelpDocSettings::~HelpDocSettings() = default;
+
+HelpDocSettings &HelpDocSettings::operator=(const HelpDocSettings &) = default;
+
+HelpDocSettings &HelpDocSettings::operator=(HelpDocSettings &&) = default;
+
+bool HelpDocSettings::addDocumentation(const QString &fileName)
+{
+    const QCompressedHelpInfo info = QCompressedHelpInfo::fromCompressedHelpFile(fileName);
+
+    if (info.isNull())
+        return false;
+
+    const QString namespaceName = info.namespaceName();
+
+    if (d->m_namespaceToFileName.contains(namespaceName))
+        return false;
+
+    if (d->m_fileNameToNamespace.contains(fileName))
+        return false;
+
+    const QString component = info.component();
+    const QVersionNumber version = info.version();
+
+    d->m_namespaceToFileName.insert(namespaceName, fileName);
+    d->m_fileNameToNamespace.insert(fileName, namespaceName);
+
+    d->m_namespaceToComponent.insert(namespaceName, component);
+    d->m_componentToNamespace[component].append(namespaceName);
+
+    d->m_namespaceToVersion.insert(namespaceName, version);
+    d->m_versionToNamespace[version].append(namespaceName);
+
+    return true;
+}
+
+bool HelpDocSettings::removeDocumentation(const QString &namespaceName)
+{
+    if (namespaceName.isEmpty())
+        return false;
+
+    const QString fileName = d->m_namespaceToFileName.value(namespaceName);
+    if (fileName.isEmpty())
+        return false;
+
+    const QString component = d->m_namespaceToComponent.value(namespaceName);
+    const QVersionNumber version = d->m_namespaceToVersion.value(namespaceName);
+
+    d->m_namespaceToComponent.remove(namespaceName);
+    d->m_namespaceToVersion.remove(namespaceName);
+    d->m_namespaceToFileName.remove(namespaceName);
+    d->m_fileNameToNamespace.remove(fileName);
+    d->m_componentToNamespace[component].removeOne(namespaceName);
+    if (d->m_componentToNamespace[component].isEmpty())
+        d->m_componentToNamespace.remove(component);
+    d->m_versionToNamespace[version].removeOne(namespaceName);
+    if (d->m_versionToNamespace[version].isEmpty())
+        d->m_versionToNamespace.remove(version);
+
+    return true;
+}
+
+QString HelpDocSettings::namespaceName(const QString &fileName) const
+{
+    return d->m_fileNameToNamespace.value(fileName);
+}
+
+QStringList HelpDocSettings::components() const
+{
+    return d->m_componentToNamespace.keys();
+}
+
+QList<QVersionNumber> HelpDocSettings::versions() const
+{
+    return d->m_versionToNamespace.keys();
+}
+
+QStringList HelpDocSettings::namespaces() const
+{
+    return d->m_namespaceToFileName.keys();
+}
+
+QMap<QString, QString> HelpDocSettings::namespaceToFileName() const
+{
+    return d->m_namespaceToFileName;
+}
+
+HelpDocSettings HelpDocSettings::readSettings(QHelpEngineCore *helpEngine)
+{
+    QHelpFilterEngine *filterEngine = helpEngine->filterEngine();
+
+    HelpDocSettings docSettings;
+    docSettings.d->m_namespaceToComponent = filterEngine->namespaceToComponent();
+    docSettings.d->m_namespaceToVersion = filterEngine->namespaceToVersion();
+    for (auto it = docSettings.d->m_namespaceToComponent.constBegin();
+         it != docSettings.d->m_namespaceToComponent.constEnd(); ++it) {
+        const QString namespaceName = it.key();
+        const QString namespaceFileName = helpEngine->documentationFileName(namespaceName);
+        docSettings.d->m_namespaceToFileName.insert(namespaceName, namespaceFileName);
+        docSettings.d->m_fileNameToNamespace.insert(namespaceFileName, namespaceName);
+        docSettings.d->m_componentToNamespace[it.value()].append(namespaceName);
+    }
+    for (auto it = docSettings.d->m_namespaceToVersion.constBegin();
+         it != docSettings.d->m_namespaceToVersion.constEnd(); ++it) {
+        docSettings.d->m_versionToNamespace[it.value()].append(it.key());
+    }
+
+    return docSettings;
+}
+
+static QMap<QString, QString> subtract(const QMap<QString, QString> &minuend,
+                                       const QMap<QString, QString> &subtrahend)
+{
+    auto result = minuend;
+
+    for (auto itSubtrahend = subtrahend.cbegin(); itSubtrahend != subtrahend.cend(); ++itSubtrahend) {
+        auto itResult = result.find(itSubtrahend.key());
+        if (itResult != result.end() && itSubtrahend.value() == itResult.value())
+            result.erase(itResult);
+    }
+
+    return result;
+}
+
+bool HelpDocSettings::applySettings(QHelpEngineCore *helpEngine,
+                                    const HelpDocSettings &settings)
+{
+    const HelpDocSettings oldSettings = readSettings(helpEngine);
+
+    const QMap<QString, QString> docsToRemove = subtract(
+                oldSettings.namespaceToFileName(),
+                settings.namespaceToFileName());
+    const QMap<QString, QString> docsToAdd = subtract(
+                settings.namespaceToFileName(),
+                oldSettings.namespaceToFileName());
+
+    bool changed = false;
+    for (const QString &namespaceName : docsToRemove.keys()) {
+        if (!helpEngine->unregisterDocumentation(namespaceName))
+            qWarning() << "Cannot unregister documentation:" << namespaceName;
+        changed = true;
+    }
+
+    for (const QString &fileName : docsToAdd.values()) {
+        if (!helpEngine->registerDocumentation(fileName))
+            qWarning() << "Cannot register documentation file:" << fileName;
+        changed = true;
+    }
+
+    return changed;
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/assistant/helpdocsettings.h b/src/assistant/assistant/helpdocsettings.h
new file mode 100644
index 000000000..7476eb63a
--- /dev/null
+++ b/src/assistant/assistant/helpdocsettings.h
@@ -0,0 +1,82 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef HELPDOCSETTINGS_H
+#define HELPDOCSETTINGS_H
+
+#include <QtCore/QSharedDataPointer>
+
+QT_BEGIN_NAMESPACE
+
+class QVersionNumber;
+class QHelpEngineCore;
+class HelpDocSettingsPrivate;
+
+class HelpDocSettings final
+{
+public:
+    HelpDocSettings();
+    HelpDocSettings(const HelpDocSettings &other);
+    HelpDocSettings(HelpDocSettings &&other);
+    ~HelpDocSettings();
+
+    HelpDocSettings &operator=(const HelpDocSettings &other);
+    HelpDocSettings &operator=(HelpDocSettings &&other);
+
+    void swap(HelpDocSettings &other) noexcept
+    { d.swap(other.d); }
+
+    bool addDocumentation(const QString &fileName);
+    bool removeDocumentation(const QString &namespaceName);
+    QString namespaceName(const QString &fileName) const;
+    QStringList components() const;
+    QList<QVersionNumber> versions() const;
+    QStringList namespaces() const;
+    QMap<QString, QString> namespaceToFileName() const;
+
+    static HelpDocSettings readSettings(QHelpEngineCore *helpEngine);
+    static bool applySettings(QHelpEngineCore *helpEngine, const HelpDocSettings &settings);
+
+private:
+    QSharedDataPointer<HelpDocSettingsPrivate> d;
+};
+
+QT_END_NAMESPACE
+
+#endif // HELPDOCSETTINGS_H
diff --git a/src/assistant/assistant/helpdocsettingswidget.cpp b/src/assistant/assistant/helpdocsettingswidget.cpp
new file mode 100644
index 000000000..94ca2b25a
--- /dev/null
+++ b/src/assistant/assistant/helpdocsettingswidget.cpp
@@ -0,0 +1,194 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "helpdocsettings.h"
+#include "helpdocsettingswidget.h"
+#include "ui_helpdocsettingswidget.h"
+
+#include <QtWidgets/QFileDialog>
+#include <QtWidgets/QPushButton>
+
+QT_BEGIN_NAMESPACE
+
+class HelpDocSettingsWidgetPrivate
+{
+    HelpDocSettingsWidget *q_ptr;
+    Q_DECLARE_PUBLIC(HelpDocSettingsWidget)
+public:
+    HelpDocSettingsWidgetPrivate() = default;
+
+    void addDocumentation();
+    void removeDocumentation();
+    void applyDocListFilter(QListWidgetItem *item);
+
+    QMap<QString, QListWidgetItem *> m_namespaceToItem;
+    QHash<QListWidgetItem *, QString> m_itemToNamespace;
+
+    Ui::HelpDocSettingsWidget m_ui;
+    HelpDocSettings m_settings;
+};
+
+void HelpDocSettingsWidgetPrivate::addDocumentation()
+{
+    Q_Q(HelpDocSettingsWidget);
+
+    const QStringList &fileNames = QFileDialog::getOpenFileNames(q,
+        q->tr("Add Documentation"), QString(), q->tr("Qt Compressed Help Files (*.qch)"));
+    if (fileNames.isEmpty())
+        return;
+
+    bool added = false;
+
+    for (const QString &fileName : fileNames) {
+        if (!m_settings.addDocumentation(fileName))
+            continue;
+
+        if (!added) {
+            added = true;
+            m_ui.registeredDocsListWidget->clearSelection();
+        }
+
+        const QString namespaceName = m_settings.namespaceName(fileName);
+        QListWidgetItem *item = new QListWidgetItem(namespaceName);
+        m_namespaceToItem.insert(namespaceName, item);
+        m_itemToNamespace.insert(item, namespaceName);
+        m_ui.registeredDocsListWidget->insertItem(m_namespaceToItem.keys().indexOf(namespaceName), item);
+
+        item->setSelected(true);
+        applyDocListFilter(item);
+    }
+
+    if (added)
+        emit q->docSettingsChanged(m_settings);
+}
+
+void HelpDocSettingsWidgetPrivate::removeDocumentation()
+{
+    Q_Q(HelpDocSettingsWidget);
+
+    const QList<QListWidgetItem *> selectedItems = m_ui.registeredDocsListWidget->selectedItems();
+    if (selectedItems.isEmpty())
+        return;
+
+    for (QListWidgetItem *item : selectedItems) {
+        const QString namespaceName = m_itemToNamespace.value(item);
+        m_itemToNamespace.remove(item);
+        m_namespaceToItem.remove(namespaceName);
+        delete item;
+
+        m_settings.removeDocumentation(namespaceName);
+    }
+
+    emit q->docSettingsChanged(m_settings);
+}
+
+void HelpDocSettingsWidgetPrivate::applyDocListFilter(QListWidgetItem *item)
+{
+    const QString namespaceName = m_itemToNamespace.value(item);
+    const QString nameFilter = m_ui.registeredDocsFilterLineEdit->text();
+
+    const bool matches = nameFilter.isEmpty() || namespaceName.contains(nameFilter);
+
+    if (!matches)
+        item->setSelected(false);
+    item->setHidden(!matches);
+}
+
+HelpDocSettingsWidget::HelpDocSettingsWidget(QWidget *parent)
+    : QWidget(parent)
+    , d_ptr(new HelpDocSettingsWidgetPrivate())
+{
+    Q_D(HelpDocSettingsWidget);
+    d->q_ptr = this;
+    d->m_ui.setupUi(this);
+
+    connect(d->m_ui.docAddButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(HelpDocSettingsWidget);
+        d->addDocumentation();
+    });
+    connect(d->m_ui.docRemoveButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(HelpDocSettingsWidget);
+        d->removeDocumentation();
+    });
+    connect(d->m_ui.registeredDocsFilterLineEdit, &QLineEdit::textChanged,
+            [this](const QString &) {
+        Q_D(HelpDocSettingsWidget);
+        for (const auto item : d->m_namespaceToItem)
+            d->applyDocListFilter(item);
+    });
+    connect(d->m_ui.registeredDocsListWidget, &QListWidget::itemSelectionChanged,
+            [this]() {
+        Q_D(HelpDocSettingsWidget);
+        d->m_ui.docRemoveButton->setEnabled(
+                    !d->m_ui.registeredDocsListWidget->selectedItems().isEmpty());
+    });
+}
+
+HelpDocSettingsWidget::~HelpDocSettingsWidget() = default;
+
+void HelpDocSettingsWidget::setDocSettings(const HelpDocSettings &settings)
+{
+    Q_D(HelpDocSettingsWidget);
+    d->m_settings = settings;
+
+    d->m_ui.registeredDocsListWidget->clear();
+    d->m_namespaceToItem.clear();
+    d->m_itemToNamespace.clear();
+
+    for (const QString &namespaceName : d->m_settings.namespaces()) {
+        QListWidgetItem *item = new QListWidgetItem(namespaceName);
+        d->m_namespaceToItem.insert(namespaceName, item);
+        d->m_itemToNamespace.insert(item, namespaceName);
+        d->m_ui.registeredDocsListWidget->addItem(item);
+        d->applyDocListFilter(item);
+    }
+
+    d->m_ui.docRemoveButton->setEnabled(
+                !d->m_ui.registeredDocsListWidget->selectedItems().isEmpty());
+}
+
+HelpDocSettings HelpDocSettingsWidget::docSettings() const
+{
+    Q_D(const HelpDocSettingsWidget);
+    return d->m_settings;
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/assistant/helpdocsettingswidget.h b/src/assistant/assistant/helpdocsettingswidget.h
new file mode 100644
index 000000000..3ed089353
--- /dev/null
+++ b/src/assistant/assistant/helpdocsettingswidget.h
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef HELPDOCSETTINGSWIDGET_H
+#define HELPDOCSETTINGSWIDGET_H
+
+#include <QtWidgets/QWidget>
+
+QT_BEGIN_NAMESPACE
+
+class HelpDocSettings;
+class HelpDocSettingsWidgetPrivate;
+
+class HelpDocSettingsWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    HelpDocSettingsWidget(QWidget *parent = nullptr);
+
+    ~HelpDocSettingsWidget();
+
+    void setDocSettings(const HelpDocSettings &settings);
+    HelpDocSettings docSettings() const;
+
+Q_SIGNALS:
+    void docSettingsChanged(const HelpDocSettings &settings);
+
+private:
+    QScopedPointer<class HelpDocSettingsWidgetPrivate> d_ptr;
+    Q_DECLARE_PRIVATE(HelpDocSettingsWidget)
+    Q_DISABLE_COPY_MOVE(HelpDocSettingsWidget)
+};
+
+QT_END_NAMESPACE
+
+#endif
+
diff --git a/src/assistant/assistant/helpdocsettingswidget.ui b/src/assistant/assistant/helpdocsettingswidget.ui
new file mode 100644
index 000000000..4897dfe86
--- /dev/null
+++ b/src/assistant/assistant/helpdocsettingswidget.ui
@@ -0,0 +1,76 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>HelpDocSettingsWidget</class>
+ <widget class="QWidget" name="HelpDocSettingsWidget">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>268</width>
+    <height>128</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0">
+    <widget class="QLabel" name="docLabel">
+     <property name="text">
+      <string>Registered Documentation</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0">
+    <widget class="QLineEdit" name="registeredDocsFilterLineEdit">
+     <property name="placeholderText">
+      <string>&lt;Filter&gt;</string>
+     </property>
+     <property name="clearButtonEnabled">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1" rowspan="2">
+    <layout class="QVBoxLayout" name="buttonLayout">
+     <item>
+      <widget class="QPushButton" name="docAddButton">
+       <property name="text">
+        <string>Add...</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="QPushButton" name="docRemoveButton">
+       <property name="text">
+        <string>Remove</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <spacer name="buttonSpacer">
+       <property name="orientation">
+        <enum>Qt::Vertical</enum>
+       </property>
+       <property name="sizeHint" stdset="0">
+        <size>
+         <width>20</width>
+         <height>40</height>
+        </size>
+       </property>
+      </spacer>
+     </item>
+    </layout>
+   </item>
+   <item row="2" column="0">
+    <widget class="QListWidget" name="registeredDocsListWidget">
+     <property name="selectionMode">
+      <enum>QAbstractItemView::ExtendedSelection</enum>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/src/assistant/assistant/helpenginewrapper.cpp b/src/assistant/assistant/helpenginewrapper.cpp
index 17e4bde8c..d69138ff8 100644
--- a/src/assistant/assistant/helpenginewrapper.cpp
+++ b/src/assistant/assistant/helpenginewrapper.cpp
@@ -670,6 +670,12 @@ void HelpEngineWrapper::setTopicChooserGeometry(const QByteArray &geometry)
     d->m_helpEngine->setCustomValue(TopicChooserGeometryKey, geometry);
 }
 
+QHelpEngineCore *HelpEngineWrapper::helpEngine() const
+{
+    return d->m_helpEngine;
+}
+
+
 // -- TimeoutForwarder
 
 TimeoutForwarder::TimeoutForwarder(const QString &fileName)
diff --git a/src/assistant/assistant/helpenginewrapper.h b/src/assistant/assistant/helpenginewrapper.h
index 6026a0473..81d8ffa1f 100644
--- a/src/assistant/assistant/helpenginewrapper.h
+++ b/src/assistant/assistant/helpenginewrapper.h
@@ -46,6 +46,7 @@ class QHelpIndexModel;
 class QHelpIndexWidget;
 class QHelpSearchEngine;
 class QHelpFilterEngine;
+class QHelpEngineCore;
 
 enum {
     ShowHomePage = 0,
@@ -175,6 +176,8 @@ public:
     const QByteArray topicChooserGeometry() const;
     void setTopicChooserGeometry(const QByteArray &geometry);
 
+    QHelpEngineCore *helpEngine() const;
+
 signals:
 
     // For asynchronous doc updates triggered by external actions.
diff --git a/src/assistant/assistant/main.cpp b/src/assistant/assistant/main.cpp
index 3ddbdbc29..cd6487751 100644
--- a/src/assistant/assistant/main.cpp
+++ b/src/assistant/assistant/main.cpp
@@ -265,69 +265,49 @@ void setupTranslations()
 
 } // Anonymous namespace.
 
-int main(int argc, char *argv[])
-{
-    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
-    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
-    QCoreApplication::setAttribute(Qt::AA_DisableWindowContextHelpButton);
-    TRACE_OBJ
-    QScopedPointer<QCoreApplication> a(createApplication(argc, argv));
-#if QT_CONFIG(library)
-    a->addLibraryPath(a->applicationDirPath() + QLatin1String("/plugins"));
-#endif
-    setupTranslations();
-
-#if defined(BROWSER_QTWEBKIT)
-    if (qobject_cast<QApplication *>(a.data())) {
-        QFont f;
-        f.setStyleHint(QFont::SansSerif);
-        QWebSettings::globalSettings()->setFontFamily(QWebSettings::StandardFont, f.defaultFamily());
-    }
-#endif // BROWSER_QTWEBKIT
-
-    // Parse arguments.
-    CmdLineParser cmd(a->arguments());
-    CmdLineParser::Result res = cmd.parse();
-    if (res == CmdLineParser::Help)
-        return 0;
-    else if (res == CmdLineParser::Error)
-        return -1;
+enum ExitStatus {
+    ExitSuccess = 0,
+    ExitFailure,
+    NoExit
+};
 
+static ExitStatus preliminarySetup(CmdLineParser *cmd)
+{
     /*
      * Create the collection objects that we need. We always have the
      * cached collection file. Depending on whether the user specified
      * one, we also may have an input collection file.
      */
-    const QString collectionFile = cmd.collectionFile();
+    const QString collectionFile = cmd->collectionFile();
     const bool collectionFileGiven = !collectionFile.isEmpty();
     QScopedPointer<QHelpEngineCore> collection;
     if (collectionFileGiven) {
         collection.reset(new QHelpEngineCore(collectionFile));
         collection->setProperty("_q_readonly", QVariant::fromValue<bool>(true));
         if (!collection->setupData()) {
-            cmd.showMessage(QCoreApplication::translate("Assistant",
-                                "Error reading collection file '%1': %2.").
-                arg(collectionFile).arg(collection->error()), true);
-            return EXIT_FAILURE;
+            cmd->showMessage(QCoreApplication::translate("Assistant",
+                             "Error reading collection file '%1': %2.")
+                            .arg(collectionFile).arg(collection->error()), true);
+            return ExitFailure;
         }
     }
     const QString &cachedCollectionFile = collectionFileGiven
-        ? constructCachedCollectionFilePath(*collection)
-        : MainWindow::defaultHelpCollectionFileName();
+            ? constructCachedCollectionFilePath(*collection)
+            : MainWindow::defaultHelpCollectionFileName();
     if (collectionFileGiven && !QFileInfo(cachedCollectionFile).exists()
-        && !collection->copyCollectionFile(cachedCollectionFile)) {
-        cmd.showMessage(QCoreApplication::translate("Assistant",
-                            "Error creating collection file '%1': %2.").
-                arg(cachedCollectionFile).arg(collection->error()), true);
-        return EXIT_FAILURE;
+            && !collection->copyCollectionFile(cachedCollectionFile)) {
+        cmd->showMessage(QCoreApplication::translate("Assistant",
+                         "Error creating collection file '%1': %2.")
+                        .arg(cachedCollectionFile).arg(collection->error()), true);
+        return ExitFailure;
     }
     QHelpEngineCore cachedCollection(cachedCollectionFile);
     if (!cachedCollection.setupData()) {
-        cmd.showMessage(QCoreApplication::translate("Assistant",
-                            "Error reading collection file '%1': %2.").
-                        arg(cachedCollectionFile).
-                        arg(cachedCollection.error()), true);
-        return EXIT_FAILURE;
+        cmd->showMessage(QCoreApplication::translate("Assistant",
+                         "Error reading collection file '%1': %2.")
+                        .arg(cachedCollectionFile)
+                        .arg(cachedCollection.error()), true);
+        return ExitFailure;
     }
 
     stripNonexistingDocs(cachedCollection);
@@ -335,56 +315,94 @@ int main(int argc, char *argv[])
         if (CollectionConfiguration::isNewer(*collection, cachedCollection))
             CollectionConfiguration::copyConfiguration(*collection,
                                                        cachedCollection);
-        if (!synchronizeDocs(*collection, cachedCollection, cmd))
-            return EXIT_FAILURE;
+        if (!synchronizeDocs(*collection, cachedCollection, *cmd))
+            return ExitFailure;
     }
 
-    if (cmd.registerRequest() != CmdLineParser::None) {
+    if (cmd->registerRequest() != CmdLineParser::None) {
         const QStringList &cachedDocs =
-            cachedCollection.registeredDocumentations();
+                cachedCollection.registeredDocumentations();
         const QString &namespaceName =
-            QHelpEngineCore::namespaceName(cmd.helpFile());
-        if (cmd.registerRequest() == CmdLineParser::Register) {
+                QHelpEngineCore::namespaceName(cmd->helpFile());
+        if (cmd->registerRequest() == CmdLineParser::Register) {
             if (collectionFileGiven
-                && !registerDocumentation(*collection, cmd, true))
-                return EXIT_FAILURE;
+                    && !registerDocumentation(*collection, *cmd, true))
+                return ExitFailure;
             if (!cachedDocs.contains(namespaceName)
-                && !registerDocumentation(cachedCollection, cmd, !collectionFileGiven))
-                return EXIT_FAILURE;
-            return EXIT_SUCCESS;
+                    && !registerDocumentation(cachedCollection, *cmd, !collectionFileGiven))
+                return ExitFailure;
+            return ExitSuccess;
         }
-        if (cmd.registerRequest() == CmdLineParser::Unregister) {
+        if (cmd->registerRequest() == CmdLineParser::Unregister) {
             if (collectionFileGiven
-                && !unregisterDocumentation(*collection, namespaceName, cmd, true))
-                return EXIT_FAILURE;
+                    && !unregisterDocumentation(*collection, namespaceName, *cmd, true))
+                return ExitFailure;
             if (cachedDocs.contains(namespaceName)
-                && !unregisterDocumentation(cachedCollection, namespaceName,
-                                            cmd, !collectionFileGiven))
-                return EXIT_FAILURE;
-            return EXIT_SUCCESS;
+                    && !unregisterDocumentation(cachedCollection, namespaceName,
+                                                *cmd, !collectionFileGiven))
+                return ExitFailure;
+            return ExitSuccess;
         }
     }
 
-    if (cmd.removeSearchIndex()) {
+    if (cmd->removeSearchIndex()) {
         return removeSearchIndex(cachedCollectionFile)
-            ? EXIT_SUCCESS : EXIT_FAILURE;
+                ? ExitSuccess : ExitFailure;
     }
 
     if (!QSqlDatabase::isDriverAvailable(QLatin1String("QSQLITE"))) {
-        cmd.showMessage(QCoreApplication::translate("Assistant",
-                            "Cannot load sqlite database driver!"),
-                        true);
-        return EXIT_FAILURE;
+        cmd->showMessage(QCoreApplication::translate("Assistant",
+                         "Cannot load sqlite database driver!"),
+                         true);
+        return ExitFailure;
     }
 
-    if (!cmd.currentFilter().isEmpty()) {
+    if (!cmd->currentFilter().isEmpty()) {
         if (collectionFileGiven)
-            collection->setCurrentFilter(cmd.currentFilter());
-        cachedCollection.setCurrentFilter(cmd.currentFilter());
+            collection->setCurrentFilter(cmd->currentFilter());
+        cachedCollection.setCurrentFilter(cmd->currentFilter());
     }
 
     if (collectionFileGiven)
-        cmd.setCollectionFile(cachedCollectionFile);
+        cmd->setCollectionFile(cachedCollectionFile);
+
+    return NoExit;
+}
+
+int main(int argc, char *argv[])
+{
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+    QCoreApplication::setAttribute(Qt::AA_DisableWindowContextHelpButton);
+    TRACE_OBJ
+    QScopedPointer<QCoreApplication> a(createApplication(argc, argv));
+#if QT_CONFIG(library)
+    a->addLibraryPath(a->applicationDirPath() + QLatin1String("/plugins"));
+#endif
+    setupTranslations();
+
+#if defined(BROWSER_QTWEBKIT)
+    if (qobject_cast<QApplication *>(a.data())) {
+        QFont f;
+        f.setStyleHint(QFont::SansSerif);
+        QWebSettings::globalSettings()->setFontFamily(QWebSettings::StandardFont, f.defaultFamily());
+    }
+#endif // BROWSER_QTWEBKIT
+
+    // Parse arguments.
+    CmdLineParser cmd(a->arguments());
+    CmdLineParser::Result res = cmd.parse();
+    if (res == CmdLineParser::Help)
+        return 0;
+    else if (res == CmdLineParser::Error)
+        return -1;
+
+    const ExitStatus status = preliminarySetup(&cmd);
+    switch (status) {
+        case ExitFailure: return EXIT_FAILURE;
+        case ExitSuccess: return EXIT_SUCCESS;
+        default: break;
+    }
 
     MainWindow *w = new MainWindow(&cmd);
     w->show();
diff --git a/src/assistant/assistant/mainwindow.cpp b/src/assistant/assistant/mainwindow.cpp
index a6b257eb7..0273129ca 100644
--- a/src/assistant/assistant/mainwindow.cpp
+++ b/src/assistant/assistant/mainwindow.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Assistant of the Qt Toolkit.
@@ -906,7 +906,7 @@ void MainWindow::showAboutDialog()
             "<p>Version %2</p>"
             "<p>Browser: %3</p></center>"
             "<p>Copyright (C) %4 The Qt Company Ltd.</p>")
-            .arg(tr("Qt Assistant"), QLatin1String(QT_VERSION_STR), browser, QStringLiteral("2019")),
+            .arg(tr("Qt Assistant"), QLatin1String(QT_VERSION_STR), browser, QStringLiteral("2020")),
             resources);
         QLatin1String path(":/qt-project.org/assistant/images/assistant-128.png");
         aboutDia.setPixmap(QString(path));
diff --git a/src/assistant/assistant/preferencesdialog.cpp b/src/assistant/assistant/preferencesdialog.cpp
index 66d6381d3..ebd2a96e8 100644
--- a/src/assistant/assistant/preferencesdialog.cpp
+++ b/src/assistant/assistant/preferencesdialog.cpp
@@ -28,42 +28,24 @@
 #include "preferencesdialog.h"
 
 #include "centralwidget.h"
-#include "filternamedialog.h"
 #include "fontpanel.h"
 #include "helpenginewrapper.h"
 #include "openpagesmanager.h"
+#include "helpdocsettingswidget.h"
 
 #include <QtCore/QVersionNumber>
+
 #include <QtGui/QFontDatabase>
-#include <QtWidgets/QMessageBox>
 
-#include <QtHelp/QCompressedHelpInfo>
 #include <QtHelp/QHelpEngineCore>
 #include <QtHelp/QHelpFilterData>
 #include <QtHelp/QHelpFilterEngine>
-
-#include <QtWidgets/QFileDialog>
+#include <QtHelp/QHelpFilterSettingsWidget>
 
 #include <QtDebug>
 
 QT_BEGIN_NAMESPACE
 
-static QStringList versionsToStringList(const QList<QVersionNumber> &versions)
-{
-    QStringList versionList;
-    for (const QVersionNumber &version : versions)
-        versionList.append(version.isNull() ? QString() : version.toString());
-    return versionList;
-}
-
-static QList<QVersionNumber> stringListToVersions(const QStringList &versionList)
-{
-    QList<QVersionNumber> versions;
-    for (const QString &versionString : versionList)
-        versions.append(QVersionNumber::fromString(versionString));
-    return versions;
-}
-
 PreferencesDialog::PreferencesDialog(QWidget *parent)
     : QDialog(parent)
     , m_appFontChanged(false)
@@ -74,18 +56,6 @@ PreferencesDialog::PreferencesDialog(QWidget *parent)
 {
     m_ui.setupUi(this);
 
-    QString resourcePath = QLatin1String(":/qt-project.org/assistant/images/");
-#ifdef Q_OS_MACOS
-    resourcePath.append(QLatin1String("mac"));
-#else
-    resourcePath.append(QLatin1String("win"));
-#endif
-
-    m_ui.filterAddButton->setIcon(QIcon(resourcePath + QLatin1String("/plus.png")));
-    m_ui.filterRemoveButton->setIcon(QIcon(resourcePath + QLatin1String("/minus.png")));
-
-    // TODO: filter docs via lineedit
-
     connect(m_ui.buttonBox->button(QDialogButtonBox::Ok), &QAbstractButton::clicked,
             this, &PreferencesDialog::okClicked);
     connect(m_ui.buttonBox->button(QDialogButtonBox::Apply), &QAbstractButton::clicked,
@@ -93,56 +63,30 @@ PreferencesDialog::PreferencesDialog(QWidget *parent)
     connect(m_ui.buttonBox->button(QDialogButtonBox::Cancel), &QAbstractButton::clicked,
             this, &QDialog::reject);
 
-    m_originalSetup = readOriginalSetup();
-    m_currentSetup = m_originalSetup;
+    m_docSettings = HelpDocSettings::readSettings(helpEngine.helpEngine());
 
     if (m_hideDocsTab) {
         m_ui.tabWidget->removeTab(m_ui.tabWidget->indexOf(m_ui.docsTab));
     } else {
-        connect(m_ui.docAddButton, &QAbstractButton::clicked,
-                this, &PreferencesDialog::addDocumentation);
-        connect(m_ui.docRemoveButton, &QAbstractButton::clicked,
-                this, &PreferencesDialog::removeDocumentation);
-        connect(m_ui.registeredDocsFilterLineEdit, &QLineEdit::textChanged,
-                this, [this](const QString &) {
-            for (const auto item : m_namespaceToItem)
-                applyDocListFilter(item);
-        });
-        connect(m_ui.registeredDocsListWidget, &QListWidget::itemSelectionChanged,
-                this, [this](){
-            m_ui.docRemoveButton->setEnabled(
-                        !m_ui.registeredDocsListWidget->selectedItems().isEmpty());
+        connect(m_ui.docSettingsWidget, &HelpDocSettingsWidget::docSettingsChanged,
+                [this](const HelpDocSettings &settings) {
+            m_docSettings = settings;
+            if (m_hideFiltersTab)
+                return;
+
+            m_ui.filterSettingsWidget->setAvailableComponents(m_docSettings.components());
+            m_ui.filterSettingsWidget->setAvailableVersions(m_docSettings.versions());
         });
 
-        updateDocumentationPage();
+        m_ui.docSettingsWidget->setDocSettings(m_docSettings);
     }
 
     if (m_hideFiltersTab) {
         m_ui.tabWidget->removeTab(m_ui.tabWidget->indexOf(m_ui.filtersTab));
     } else {
-        connect(m_ui.componentWidget, &OptionsWidget::optionSelectionChanged,
-                this, &PreferencesDialog::componentsChanged);
-        connect(m_ui.versionWidget, &OptionsWidget::optionSelectionChanged,
-                this, &PreferencesDialog::versionsChanged);
-        connect(m_ui.filterWidget, &QListWidget::currentItemChanged,
-                this, &PreferencesDialog::filterSelected);
-        connect(m_ui.filterWidget, &QListWidget::itemDoubleClicked,
-                this, &PreferencesDialog::renameFilterClicked);
-
-        // TODO: repeat these actions on context menu
-        connect(m_ui.filterAddButton, &QAbstractButton::clicked,
-                this, &PreferencesDialog::addFilterClicked);
-        connect(m_ui.filterRenameButton, &QAbstractButton::clicked,
-                this, &PreferencesDialog::renameFilterClicked);
-        connect(m_ui.filterRemoveButton, &QAbstractButton::clicked,
-                this, &PreferencesDialog::removeFilterClicked);
-
-        m_ui.componentWidget->setNoOptionText(tr("No Component"));
-        m_ui.componentWidget->setInvalidOptionText(tr("Invalid Component"));
-        m_ui.versionWidget->setNoOptionText(tr("No Version"));
-        m_ui.versionWidget->setInvalidOptionText(tr("Invalid Version"));
-
-        updateFilterPage();
+        m_ui.filterSettingsWidget->setAvailableComponents(m_docSettings.components());
+        m_ui.filterSettingsWidget->setAvailableVersions(m_docSettings.versions());
+        m_ui.filterSettingsWidget->readSettings(helpEngine.filterEngine());
     }
 
     updateFontSettingsPage();
@@ -152,331 +96,6 @@ PreferencesDialog::PreferencesDialog(QWidget *parent)
         setFont(helpEngine.appFont());
 }
 
-FilterSetup PreferencesDialog::readOriginalSetup() const
-{
-    FilterSetup filterSetup;
-
-    filterSetup.m_namespaceToComponent = helpEngine.filterEngine()->namespaceToComponent();
-    filterSetup.m_namespaceToVersion = helpEngine.filterEngine()->namespaceToVersion();
-    for (auto it = filterSetup.m_namespaceToComponent.constBegin();
-         it != filterSetup.m_namespaceToComponent.constEnd(); ++it) {
-        const QString namespaceName = it.key();
-        const QString namespaceFileName = helpEngine.documentationFileName(namespaceName);
-        filterSetup.m_namespaceToFileName.insert(namespaceName, namespaceFileName);
-        filterSetup.m_fileNameToNamespace.insert(namespaceFileName, namespaceName);
-        filterSetup.m_componentToNamespace[it.value()].append(namespaceName);
-    }
-    for (auto it = filterSetup.m_namespaceToVersion.constBegin();
-         it != filterSetup.m_namespaceToVersion.constEnd(); ++it) {
-        filterSetup.m_versionToNamespace[it.value()].append(it.key());
-    }
-
-    const QStringList allFilters = helpEngine.filterEngine()->filters();
-    for (const QString &filter : allFilters)
-        filterSetup.m_filterToData.insert(filter, helpEngine.filterEngine()->filterData(filter));
-
-    filterSetup.m_currentFilter = helpEngine.filterEngine()->activeFilter();
-
-    return filterSetup;
-}
-
-void PreferencesDialog::updateFilterPage()
-{
-    if (m_hideFiltersTab)
-        return;
-
-    QString currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
-    if (currentFilter.isEmpty())
-        currentFilter = m_currentSetup.m_currentFilter;
-
-    m_currentSetup = m_originalSetup;
-
-    m_ui.filterWidget->clear();
-    m_ui.componentWidget->clear();
-    m_ui.versionWidget->clear();
-    m_itemToFilter.clear();
-    m_filterToItem.clear();
-
-    for (const QString &filterName : m_currentSetup.m_filterToData.keys()) {
-        QListWidgetItem *item = new QListWidgetItem(filterName);
-        m_ui.filterWidget->addItem(item);
-        m_itemToFilter.insert(item, filterName);
-        m_filterToItem.insert(filterName, item);
-        if (filterName == currentFilter)
-            m_ui.filterWidget->setCurrentItem(item);
-    }
-
-    if (!m_ui.filterWidget->currentItem() && !m_filterToItem.isEmpty())
-        m_ui.filterWidget->setCurrentItem(m_filterToItem.first());
-
-    updateCurrentFilter();
-}
-
-void PreferencesDialog::updateCurrentFilter()
-{
-    if (m_hideFiltersTab)
-        return;
-
-    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
-
-    const bool filterSelected = !currentFilter.isEmpty();
-    m_ui.componentWidget->setEnabled(filterSelected);
-    m_ui.versionWidget->setEnabled(filterSelected);
-    m_ui.filterRenameButton->setEnabled(filterSelected);
-    m_ui.filterRemoveButton->setEnabled(filterSelected);
-
-    m_ui.componentWidget->setOptions(m_currentSetup.m_componentToNamespace.keys(),
-            m_currentSetup.m_filterToData.value(currentFilter).components());
-    m_ui.versionWidget->setOptions(versionsToStringList(m_currentSetup.m_versionToNamespace.keys()),
-            versionsToStringList(m_currentSetup.m_filterToData.value(currentFilter).versions()));
-}
-
-void PreferencesDialog::updateDocumentationPage()
-{
-    if (m_hideDocsTab)
-        return;
-
-    m_ui.registeredDocsListWidget->clear();
-    m_namespaceToItem.clear();
-    m_itemToNamespace.clear();
-
-    for (const QString &namespaceName : m_currentSetup.m_namespaceToFileName.keys()) {
-        QListWidgetItem *item = new QListWidgetItem(namespaceName);
-        m_namespaceToItem.insert(namespaceName, item);
-        m_itemToNamespace.insert(item, namespaceName);
-        applyDocListFilter(item);
-        m_ui.registeredDocsListWidget->addItem(item);
-    }
-    m_ui.docRemoveButton->setEnabled(
-                !m_ui.registeredDocsListWidget->selectedItems().isEmpty());
-}
-
-void PreferencesDialog::applyDocListFilter(QListWidgetItem *item)
-{
-    const QString namespaceName = m_itemToNamespace.value(item);
-    const QString nameFilter = m_ui.registeredDocsFilterLineEdit->text();
-
-    const bool matches = nameFilter.isEmpty() || namespaceName.contains(nameFilter);
-
-    if (!matches)
-        item->setSelected(false);
-    item->setHidden(!matches);
-}
-
-void PreferencesDialog::filterSelected(QListWidgetItem *item)
-{
-    Q_UNUSED(item)
-
-    updateCurrentFilter();
-}
-
-void PreferencesDialog::componentsChanged(const QStringList &components)
-{
-    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
-    if (currentFilter.isEmpty())
-        return;
-
-    m_currentSetup.m_filterToData[currentFilter].setComponents(components);
-}
-
-void PreferencesDialog::versionsChanged(const QStringList &versions)
-{
-    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
-    if (currentFilter.isEmpty())
-        return;
-
-    m_currentSetup.m_filterToData[currentFilter].setVersions(stringListToVersions(versions));
-}
-
-QString PreferencesDialog::suggestedNewFilterName(const QString &initialFilterName) const
-{
-    QString newFilterName = initialFilterName;
-
-    int counter = 1;
-    while (m_filterToItem.contains(newFilterName)) {
-        newFilterName = initialFilterName + QLatin1Char(' ')
-                + QString::number(++counter);
-    }
-
-    return newFilterName;
-}
-
-QString PreferencesDialog::getUniqueFilterName(const QString &windowTitle,
-                                               const QString &initialFilterName)
-{
-    QString newFilterName = initialFilterName;
-    while (1) {
-        FilterNameDialog dialog(this);
-        dialog.setWindowTitle(windowTitle);
-        dialog.setFilterName(newFilterName);
-        if (dialog.exec() == QDialog::Rejected)
-            return QString();
-
-        newFilterName = dialog.filterName();
-        if (!m_filterToItem.contains(newFilterName))
-            break;
-
-        if (QMessageBox::warning(this, tr("Filter Exists"),
-                                 tr("The filter \"%1\" already exists.")
-                                 .arg(newFilterName),
-                                 QMessageBox::Retry | QMessageBox::Cancel)
-                == QMessageBox::Cancel) {
-            return QString();
-        }
-    }
-
-    return newFilterName;
-}
-
-void PreferencesDialog::addFilterClicked()
-{
-    const QString newFilterName = getUniqueFilterName(tr("Add Filter"),
-                                  suggestedNewFilterName(tr("New Filter")));
-    if (newFilterName.isEmpty())
-        return;
-
-    addFilter(newFilterName);
-}
-
-void PreferencesDialog::renameFilterClicked()
-{
-    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
-    if (currentFilter.isEmpty())
-        return;
-
-    const QString newFilterName = getUniqueFilterName(tr("Rename Filter"), currentFilter);
-    if (newFilterName.isEmpty())
-        return;
-
-    const QHelpFilterData oldFilterData = m_currentSetup.m_filterToData.value(currentFilter);
-    removeFilter(currentFilter);
-    addFilter(newFilterName, oldFilterData);
-
-    if (m_currentSetup.m_currentFilter == currentFilter)
-        m_currentSetup.m_currentFilter = newFilterName;
-}
-
-void PreferencesDialog::removeFilterClicked()
-{
-    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
-    if (currentFilter.isEmpty())
-        return;
-
-    if (QMessageBox::question(this, tr("Remove Filter"),
-                              tr("Are you sure you want to remove the \"%1\" filter?")
-                              .arg(currentFilter),
-                              QMessageBox::Yes | QMessageBox::No)
-            != QMessageBox::Yes) {
-        return;
-    }
-
-    removeFilter(currentFilter);
-
-    if (m_currentSetup.m_currentFilter == currentFilter)
-        m_currentSetup.m_currentFilter.clear();
-}
-
-void PreferencesDialog::addFilter(const QString &filterName,
-                                  const QHelpFilterData &filterData)
-{
-    QListWidgetItem *item = new QListWidgetItem(filterName);
-    m_currentSetup.m_filterToData.insert(filterName, filterData);
-    m_filterToItem.insert(filterName, item);
-    m_itemToFilter.insert(item, filterName);
-    m_ui.filterWidget->insertItem(m_filterToItem.keys().indexOf(filterName), item);
-
-    m_ui.filterWidget->setCurrentItem(item);
-    updateCurrentFilter();
-}
-
-void PreferencesDialog::removeFilter(const QString &filterName)
-{
-    QListWidgetItem *item = m_filterToItem.value(filterName);
-    m_itemToFilter.remove(item);
-    m_filterToItem.remove(filterName);
-    delete item;
-
-    m_currentSetup.m_filterToData.remove(filterName);
-}
-
-void PreferencesDialog::addDocumentation()
-{
-    const QStringList &fileNames = QFileDialog::getOpenFileNames(this,
-        tr("Add Documentation"), QString(), tr("Qt Compressed Help Files (*.qch)"));
-    if (fileNames.isEmpty())
-        return;
-
-    bool added = false;
-
-    for (const QString &fileName : fileNames) {
-        const QCompressedHelpInfo info = QCompressedHelpInfo::fromCompressedHelpFile(fileName);
-        const QString namespaceName = info.namespaceName();
-
-        if (m_currentSetup.m_namespaceToFileName.contains(namespaceName))
-            continue;
-
-        if (m_currentSetup.m_fileNameToNamespace.contains(fileName))
-            continue;
-
-        const QString component = info.component();
-        const QVersionNumber version = info.version();
-
-        m_currentSetup.m_namespaceToFileName.insert(namespaceName, fileName);
-        m_currentSetup.m_fileNameToNamespace.insert(fileName, namespaceName);
-
-        m_currentSetup.m_namespaceToComponent.insert(namespaceName, component);
-        m_currentSetup.m_componentToNamespace[component].append(namespaceName);
-
-        m_currentSetup.m_namespaceToVersion.insert(namespaceName, version);
-        m_currentSetup.m_versionToNamespace[version].append(namespaceName);
-
-        if (!added) {
-            added = true;
-            m_ui.registeredDocsListWidget->clearSelection();
-        }
-
-        QListWidgetItem *item = new QListWidgetItem(namespaceName);
-        m_namespaceToItem.insert(namespaceName, item);
-        m_itemToNamespace.insert(item, namespaceName);
-        m_ui.registeredDocsListWidget->insertItem(m_namespaceToItem.keys().indexOf(namespaceName), item);
-        item->setSelected(true);
-        applyDocListFilter(item);
-    }
-
-    if (added)
-        updateCurrentFilter();
-}
-
-void PreferencesDialog::removeDocumentation()
-{
-    const QList<QListWidgetItem *> selectedItems = m_ui.registeredDocsListWidget->selectedItems();
-    if (selectedItems.isEmpty())
-        return;
-
-    for (QListWidgetItem *item : selectedItems) {
-        const QString namespaceName = m_itemToNamespace.value(item);
-        m_itemToNamespace.remove(item);
-        m_namespaceToItem.remove(namespaceName);
-        delete item;
-
-        const QString fileName = m_currentSetup.m_namespaceToFileName.value(namespaceName);
-        const QString component = m_currentSetup.m_namespaceToComponent.value(namespaceName);
-        const QVersionNumber version = m_currentSetup.m_namespaceToVersion.value(namespaceName);
-        m_currentSetup.m_namespaceToComponent.remove(namespaceName);
-        m_currentSetup.m_namespaceToVersion.remove(namespaceName);
-        m_currentSetup.m_namespaceToFileName.remove(namespaceName);
-        m_currentSetup.m_fileNameToNamespace.remove(fileName);
-        m_currentSetup.m_componentToNamespace[component].removeOne(namespaceName);
-        if (m_currentSetup.m_componentToNamespace[component].isEmpty())
-            m_currentSetup.m_componentToNamespace.remove(component);
-        m_currentSetup.m_versionToNamespace[version].removeOne(namespaceName);
-        if (m_currentSetup.m_versionToNamespace[version].isEmpty())
-            m_currentSetup.m_versionToNamespace.remove(version);
-    }
-
-    updateCurrentFilter();
-}
-
 void PreferencesDialog::okClicked()
 {
     applyChanges();
@@ -486,74 +105,27 @@ void PreferencesDialog::okClicked()
 void PreferencesDialog::applyClicked()
 {
     applyChanges();
-    m_originalSetup = readOriginalSetup();
-    m_currentSetup = m_originalSetup;
-    updateDocumentationPage();
-    updateFilterPage();
-}
 
-template <class T>
-static QMap<QString, T> subtract(const QMap<QString, T> &minuend,
-                                 const QMap<QString, T> &subtrahend)
-{
-    QMap<QString, T> result = minuend;
+    m_docSettings = HelpDocSettings::readSettings(helpEngine.helpEngine());
 
-    for (auto itSubtrahend = subtrahend.cbegin(); itSubtrahend != subtrahend.cend(); ++itSubtrahend) {
-        auto itResult = result.find(itSubtrahend.key());
-        if (itResult != result.end() && itSubtrahend.value() == itResult.value())
-            result.erase(itResult);
+    if (!m_hideDocsTab)
+        m_ui.docSettingsWidget->setDocSettings(m_docSettings);
+    if (!m_hideFiltersTab) {
+        m_ui.filterSettingsWidget->setAvailableComponents(m_docSettings.components());
+        m_ui.filterSettingsWidget->setAvailableVersions(m_docSettings.versions());
+        m_ui.filterSettingsWidget->readSettings(helpEngine.filterEngine());
     }
-
-    return result;
 }
 
 void PreferencesDialog::applyChanges()
 {
     bool changed = false;
-
-    const QMap<QString, QString> docsToRemove = subtract(
-                m_originalSetup.m_namespaceToFileName,
-                m_currentSetup.m_namespaceToFileName);
-    const QMap<QString, QString> docsToAdd = subtract(
-                m_currentSetup.m_namespaceToFileName,
-                m_originalSetup.m_namespaceToFileName);
-
-    for (const QString &namespaceName : docsToRemove.keys()) {
-        if (!helpEngine.unregisterDocumentation(namespaceName))
-            qWarning() << "Cannot unregister documentation:" << namespaceName;
-        changed = true;
-    }
-
-    for (const QString &fileName : docsToAdd.values()) {
-        if (!helpEngine.registerDocumentation(fileName))
-            qWarning() << "Cannot register documentation file:" << fileName;
-        changed = true;
-    }
-
-    const QMap<QString, QHelpFilterData> filtersToRemove = subtract(
-                m_originalSetup.m_filterToData,
-                m_currentSetup.m_filterToData);
-    const QMap<QString, QHelpFilterData> filtersToAdd = subtract(
-                m_currentSetup.m_filterToData,
-                m_originalSetup.m_filterToData);
-
-    const QString &currentFilter = helpEngine.filterEngine()->activeFilter();
-
-    for (const QString &filter : filtersToRemove.keys()) {
-        helpEngine.filterEngine()->removeFilter(filter);
-        if (currentFilter == filter && !filtersToAdd.contains(filter))
-            helpEngine.filterEngine()->setActiveFilter(QString());
-        changed = true;
-    }
-
-    for (auto it = filtersToAdd.cbegin(); it != filtersToAdd.cend(); ++it) {
-        helpEngine.filterEngine()->setFilterData(it.key(), it.value());
-        changed = true;
-    }
+    if (!m_hideDocsTab)
+        changed = HelpDocSettings::applySettings(helpEngine.helpEngine(), m_docSettings);
+    if (!m_hideFiltersTab)
+        changed = changed || m_ui.filterSettingsWidget->applySettings(helpEngine.filterEngine());
 
     if (changed) {
-        helpEngine.filterEngine()->setActiveFilter(m_currentSetup.m_currentFilter);
-
         // In order to update the filtercombobox and indexwidget
         // according to the new filter configuration.
         helpEngine.setupData();
diff --git a/src/assistant/assistant/preferencesdialog.h b/src/assistant/assistant/preferencesdialog.h
index b0601e280..a65066fde 100644
--- a/src/assistant/assistant/preferencesdialog.h
+++ b/src/assistant/assistant/preferencesdialog.h
@@ -29,31 +29,17 @@
 #ifndef PREFERENCESDIALOG_H
 #define PREFERENCESDIALOG_H
 
-#include <QtCore/QVersionNumber>
+#include <QtCore/QMap>
 #include <QtWidgets/QDialog>
 #include <QtHelp/QHelpFilterData>
 #include "ui_preferencesdialog.h"
+#include "helpdocsettings.h"
 
 QT_BEGIN_NAMESPACE
 
 class FontPanel;
 class HelpEngineWrapper;
 class QFileSystemWatcher;
-class QVersionNumber;
-
-struct FilterSetup {
-    QMap<QString, QString>            m_namespaceToComponent;
-    QMap<QString, QStringList>        m_componentToNamespace;
-
-    QMap<QString, QVersionNumber>     m_namespaceToVersion;
-    QMap<QVersionNumber, QStringList> m_versionToNamespace;
-
-    QMap<QString, QString>            m_namespaceToFileName;
-    QMap<QString, QString>            m_fileNameToNamespace;
-
-    QMap<QString, QHelpFilterData>    m_filterToData;
-    QString                           m_currentFilter;
-};
 
 class PreferencesDialog : public QDialog
 {
@@ -63,17 +49,6 @@ public:
     PreferencesDialog(QWidget *parent = nullptr);
 
 private slots:
-    void filterSelected(QListWidgetItem *item);
-    void componentsChanged(const QStringList &components);
-    void versionsChanged(const QStringList &versions);
-    void addFilterClicked();
-    void renameFilterClicked();
-    void removeFilterClicked();
-    void addFilter(const QString &filterName,
-                   const QHelpFilterData &filterData = QHelpFilterData());
-    void removeFilter(const QString &filterName);
-    void addDocumentation();
-    void removeDocumentation();
     void okClicked();
     void applyClicked();
     void applyChanges();
@@ -92,28 +67,12 @@ signals:
     void updateUserInterface();
 
 private:
-    QString suggestedNewFilterName(const QString &initialFilterName) const;
-    QString getUniqueFilterName(const QString &windowTitle,
-                                const QString &initialFilterName = QString());
-    void applyDocListFilter(QListWidgetItem *item);
-
-    void updateFilterPage();
-    void updateCurrentFilter();
-    void updateDocumentationPage();
     void updateFontSettingsPage();
     void updateOptionsPage();
-    FilterSetup readOriginalSetup() const;
 
     Ui::PreferencesDialogClass m_ui;
 
-    FilterSetup m_originalSetup;
-    FilterSetup m_currentSetup;
-
-    QMap<QString, QListWidgetItem *> m_namespaceToItem;
-    QHash<QListWidgetItem *, QString> m_itemToNamespace;
-
-    QMap<QString, QListWidgetItem *> m_filterToItem;
-    QHash<QListWidgetItem *, QString> m_itemToFilter;
+    HelpDocSettings m_docSettings;
 
     FontPanel *m_appFontPanel;
     FontPanel *m_browserFontPanel;
diff --git a/src/assistant/assistant/preferencesdialog.ui b/src/assistant/assistant/preferencesdialog.ui
index 68dbf68e2..2d1c480a6 100644
--- a/src/assistant/assistant/preferencesdialog.ui
+++ b/src/assistant/assistant/preferencesdialog.ui
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>395</width>
-    <height>341</height>
+    <height>376</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -17,7 +17,7 @@
    <item>
     <widget class="QTabWidget" name="tabWidget">
      <property name="currentIndex">
-      <number>1</number>
+      <number>2</number>
      </property>
      <widget class="QWidget" name="fontsTab">
       <attribute name="title">
@@ -69,60 +69,21 @@
       <attribute name="title">
        <string>Filters</string>
       </attribute>
-      <layout class="QGridLayout" name="gridLayout_2">
-       <item row="0" column="3">
-        <widget class="QLabel" name="componentsLabel">
-         <property name="frameShape">
-          <enum>QFrame::NoFrame</enum>
-         </property>
-         <property name="text">
-          <string>Components:</string>
-         </property>
-        </widget>
-       </item>
-       <item row="0" column="4">
-        <widget class="QLabel" name="versionsLabel">
-         <property name="text">
-          <string>Versions:</string>
-         </property>
-        </widget>
-       </item>
-       <item row="1" column="0" colspan="3">
-        <widget class="QListWidget" name="filterWidget"/>
-       </item>
-       <item row="1" column="3" rowspan="2">
-        <widget class="OptionsWidget" name="componentWidget" native="true"/>
-       </item>
-       <item row="1" column="4" rowspan="2">
-        <widget class="OptionsWidget" name="versionWidget" native="true"/>
-       </item>
-       <item row="2" column="0">
-        <widget class="QToolButton" name="filterAddButton">
-         <property name="text">
-          <string>Add...</string>
-         </property>
-        </widget>
-       </item>
-       <item row="2" column="1">
-        <widget class="QToolButton" name="filterRenameButton">
-         <property name="text">
-          <string>Rename...</string>
-         </property>
-        </widget>
-       </item>
-       <item row="2" column="2">
-        <widget class="QToolButton" name="filterRemoveButton">
-         <property name="text">
-          <string>Remove</string>
-         </property>
-        </widget>
-       </item>
-       <item row="0" column="0" colspan="3">
-        <widget class="QLabel" name="filterLabel">
-         <property name="text">
-          <string>Filter:</string>
-         </property>
-        </widget>
+      <layout class="QVBoxLayout" name="verticalLayout_5">
+       <property name="leftMargin">
+        <number>0</number>
+       </property>
+       <property name="topMargin">
+        <number>0</number>
+       </property>
+       <property name="rightMargin">
+        <number>0</number>
+       </property>
+       <property name="bottomMargin">
+        <number>0</number>
+       </property>
+       <item>
+        <widget class="QHelpFilterSettingsWidget" name="filterSettingsWidget" native="true"/>
        </item>
       </layout>
      </widget>
@@ -130,61 +91,21 @@
       <attribute name="title">
        <string>Documentation</string>
       </attribute>
-      <layout class="QGridLayout" name="gridLayout_3">
-       <item row="0" column="0">
-        <widget class="QLabel" name="label_3">
-         <property name="text">
-          <string>Registered Documentation:</string>
-         </property>
-        </widget>
-       </item>
-       <item row="1" column="0">
-        <widget class="QLineEdit" name="registeredDocsFilterLineEdit">
-         <property name="placeholderText">
-          <string>&lt;Filter&gt;</string>
-         </property>
-         <property name="clearButtonEnabled">
-          <bool>true</bool>
-         </property>
-        </widget>
-       </item>
-       <item row="1" column="1" rowspan="2">
-        <layout class="QVBoxLayout" name="verticalLayout_4">
-         <item>
-          <widget class="QPushButton" name="docAddButton">
-           <property name="text">
-            <string>Add...</string>
-           </property>
-          </widget>
-         </item>
-         <item>
-          <widget class="QPushButton" name="docRemoveButton">
-           <property name="text">
-            <string>Remove</string>
-           </property>
-          </widget>
-         </item>
-         <item>
-          <spacer>
-           <property name="orientation">
-            <enum>Qt::Vertical</enum>
-           </property>
-           <property name="sizeHint" stdset="0">
-            <size>
-             <width>20</width>
-             <height>40</height>
-            </size>
-           </property>
-          </spacer>
-         </item>
-        </layout>
-       </item>
-       <item row="2" column="0">
-        <widget class="QListWidget" name="registeredDocsListWidget">
-         <property name="selectionMode">
-          <enum>QAbstractItemView::ExtendedSelection</enum>
-         </property>
-        </widget>
+      <layout class="QVBoxLayout" name="verticalLayout_4">
+       <property name="leftMargin">
+        <number>0</number>
+       </property>
+       <property name="topMargin">
+        <number>0</number>
+       </property>
+       <property name="rightMargin">
+        <number>0</number>
+       </property>
+       <property name="bottomMargin">
+        <number>0</number>
+       </property>
+       <item>
+        <widget class="HelpDocSettingsWidget" name="docSettingsWidget" native="true"/>
        </item>
       </layout>
      </widget>
@@ -359,9 +280,15 @@
  <layoutdefault spacing="6" margin="11"/>
  <customwidgets>
   <customwidget>
-   <class>OptionsWidget</class>
+   <class>HelpDocSettingsWidget</class>
+   <extends>QWidget</extends>
+   <header>helpdocsettingswidget.h</header>
+   <container>1</container>
+  </customwidget>
+  <customwidget>
+   <class>QHelpFilterSettingsWidget</class>
    <extends>QWidget</extends>
-   <header>optionswidget.h</header>
+   <header>qhelpfiltersettingswidget.h</header>
    <container>1</container>
   </customwidget>
  </customwidgets>
diff --git a/src/assistant/help/help.pro b/src/assistant/help/help.pro
index cd7781dde..ff7a81374 100644
--- a/src/assistant/help/help.pro
+++ b/src/assistant/help/help.pro
@@ -12,10 +12,13 @@ DEFINES -= QT_ASCII_CAST_WARNINGS
 RESOURCES += helpsystem.qrc
 SOURCES += \
     qcompressedhelpinfo.cpp \
+    qfilternamedialog.cpp \
     qhelpenginecore.cpp \
     qhelpengine.cpp \
     qhelpfilterdata.cpp \
     qhelpfilterengine.cpp \
+    qhelpfiltersettings.cpp \
+    qhelpfiltersettingswidget.cpp \
     qhelpdbreader.cpp \
     qhelpcontentwidget.cpp \
     qhelpindexwidget.cpp \
@@ -26,15 +29,19 @@ SOURCES += \
     qhelpsearchindexwriter_default.cpp \
     qhelpsearchindexreader_default.cpp \
     qhelpsearchindexreader.cpp \
-    qhelp_global.cpp
+    qhelp_global.cpp \
+    qoptionswidget.cpp
 
 HEADERS += \
     qcompressedhelpinfo.h \
+    qfilternamedialog_p.h \
     qhelpenginecore.h \
     qhelpengine.h \
     qhelpengine_p.h \
     qhelpfilterdata.h \
     qhelpfilterengine.h \
+    qhelpfiltersettings_p.h \
+    qhelpfiltersettingswidget.h \
     qhelp_global.h \
     qhelpdbreader_p.h \
     qhelpcontentwidget.h \
@@ -45,6 +52,12 @@ HEADERS += \
     qhelpsearchresultwidget.h \
     qhelpsearchindexwriter_default_p.h \
     qhelpsearchindexreader_default_p.h \
-    qhelpsearchindexreader_p.h
+    qhelpsearchindexreader_p.h \
+    qoptionswidget_p.h
+
+FORMS += \
+    qhelpfiltersettingswidget.ui \
+    qfilternamedialog.ui
+
 
 load(qt_module)
diff --git a/src/assistant/help/helpsystem.qrc b/src/assistant/help/helpsystem.qrc
index 785923aad..611008639 100644
--- a/src/assistant/help/helpsystem.qrc
+++ b/src/assistant/help/helpsystem.qrc
@@ -4,5 +4,9 @@
         <file>images/1rightarrow.png</file>
         <file>images/3leftarrow.png</file>
         <file>images/3rightarrow.png</file>
+        <file>images/mac/minus.png</file>
+        <file>images/mac/plus.png</file>
+        <file>images/win/minus.png</file>
+        <file>images/win/plus.png</file>
     </qresource>
 </RCC>
diff --git a/src/assistant/assistant/images/mac/minus.png b/src/assistant/help/images/mac/minus.png
index 8d2eaed52..8d2eaed52 100644
--- a/src/assistant/assistant/images/mac/minus.png
+++ b/src/assistant/help/images/mac/minus.png
diff --git a/src/assistant/assistant/images/mac/plus.png b/src/assistant/help/images/mac/plus.png
index 1ee45423e..1ee45423e 100644
--- a/src/assistant/assistant/images/mac/plus.png
+++ b/src/assistant/help/images/mac/plus.png
diff --git a/src/assistant/assistant/images/win/minus.png b/src/assistant/help/images/win/minus.png
index c0dc274bb..c0dc274bb 100644
--- a/src/assistant/assistant/images/win/minus.png
+++ b/src/assistant/help/images/win/minus.png
diff --git a/src/assistant/assistant/images/win/plus.png b/src/assistant/help/images/win/plus.png
index ecf058941..ecf058941 100644
--- a/src/assistant/assistant/images/win/plus.png
+++ b/src/assistant/help/images/win/plus.png
diff --git a/src/assistant/help/qcompressedhelpinfo.cpp b/src/assistant/help/qcompressedhelpinfo.cpp
index bbdc64157..a3c5b75d5 100644
--- a/src/assistant/help/qcompressedhelpinfo.cpp
+++ b/src/assistant/help/qcompressedhelpinfo.cpp
@@ -55,12 +55,14 @@ public:
         , m_namespaceName(other.m_namespaceName)
         , m_component(other.m_component)
         , m_version(other.m_version)
+        , m_isNull(other.m_isNull)
     { }
     ~QCompressedHelpInfoPrivate() = default;
 
     QString m_namespaceName;
     QString m_component;
     QVersionNumber m_version;
+    bool m_isNull = true;
 };
 
 /*!
@@ -151,6 +153,15 @@ QVersionNumber QCompressedHelpInfo::version() const
 }
 
 /*!
+    Returns \c true if the info is invalid, otherwise returns
+    \c false.
+*/
+bool QCompressedHelpInfo::isNull() const
+{
+    return d->m_isNull;
+}
+
+/*!
     Returns the QCompressedHelpInfo instance for the
     \a documentationFileName of the existing qch file.
 */
@@ -164,6 +175,7 @@ QCompressedHelpInfo QCompressedHelpInfo::fromCompressedHelpFile(const QString &d
         info.d->m_namespaceName = reader.namespaceName();
         info.d->m_component = reader.virtualFolder();
         info.d->m_version = QVersionNumber::fromString(reader.version());
+        info.d->m_isNull = false;
         return info;
     }
     return QCompressedHelpInfo();
diff --git a/src/assistant/help/qcompressedhelpinfo.h b/src/assistant/help/qcompressedhelpinfo.h
index c392bb74c..7b3c78c12 100644
--- a/src/assistant/help/qcompressedhelpinfo.h
+++ b/src/assistant/help/qcompressedhelpinfo.h
@@ -66,6 +66,7 @@ public:
     QString namespaceName() const;
     QString component() const;
     QVersionNumber version() const;
+    bool isNull() const;
 
     static QCompressedHelpInfo fromCompressedHelpFile(const QString &documentationFileName);
 
diff --git a/src/assistant/assistant/filternamedialog.cpp b/src/assistant/help/qfilternamedialog.cpp
index 4c17d3332..8563a3355 100644
--- a/src/assistant/assistant/filternamedialog.cpp
+++ b/src/assistant/help/qfilternamedialog.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Assistant of the Qt Toolkit.
@@ -28,11 +28,11 @@
 
 #include <QtWidgets/QPushButton>
 
-#include "filternamedialog.h"
+#include "qfilternamedialog_p.h"
 
 QT_BEGIN_NAMESPACE
 
-FilterNameDialog::FilterNameDialog(QWidget *parent)
+QFilterNameDialog::QFilterNameDialog(QWidget *parent)
     : QDialog(parent)
 {
     m_ui.setupUi(this);
@@ -41,22 +41,22 @@ FilterNameDialog::FilterNameDialog(QWidget *parent)
     connect(m_ui.buttonBox->button(QDialogButtonBox::Cancel), &QAbstractButton::clicked,
             this, &QDialog::reject);
     connect(m_ui.lineEdit, &QLineEdit::textChanged,
-            this, &FilterNameDialog::updateOkButton);
+            this, &QFilterNameDialog::updateOkButton);
     m_ui.buttonBox->button(QDialogButtonBox::Ok)->setDisabled(true);
 }
 
-void FilterNameDialog::setFilterName(const QString &filter)
+void QFilterNameDialog::setFilterName(const QString &filter)
 {
     m_ui.lineEdit->setText(filter);
     m_ui.lineEdit->selectAll();
 }
 
-QString FilterNameDialog::filterName() const
+QString QFilterNameDialog::filterName() const
 {
     return m_ui.lineEdit->text();
 }
 
-void FilterNameDialog::updateOkButton()
+void QFilterNameDialog::updateOkButton()
 {
     m_ui.buttonBox->button(QDialogButtonBox::Ok)
         ->setDisabled(m_ui.lineEdit->text().isEmpty());
diff --git a/src/assistant/assistant/filternamedialog.ui b/src/assistant/help/qfilternamedialog.ui
index 1da584a80..1da584a80 100644
--- a/src/assistant/assistant/filternamedialog.ui
+++ b/src/assistant/help/qfilternamedialog.ui
diff --git a/src/assistant/assistant/filternamedialog.h b/src/assistant/help/qfilternamedialog_p.h
index 522b611af..f805e9308 100644
--- a/src/assistant/assistant/filternamedialog.h
+++ b/src/assistant/help/qfilternamedialog_p.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Assistant of the Qt Toolkit.
@@ -26,20 +26,20 @@
 **
 ****************************************************************************/
 
-#ifndef FILTERNAMEDIALOG_H
-#define FILTERNAMEDIALOG_H
+#ifndef QFILTERNAMEDIALOG_H
+#define QFILTERNAMEDIALOG_H
 
 #include <QtWidgets/QDialog>
-#include "ui_filternamedialog.h"
+#include "ui_qfilternamedialog.h"
 
 QT_BEGIN_NAMESPACE
 
-class FilterNameDialog : public QDialog
+class QFilterNameDialog : public QDialog
 {
     Q_OBJECT
 
 public:
-    FilterNameDialog(QWidget *parent = nullptr);
+    QFilterNameDialog(QWidget *parent = nullptr);
 
     void setFilterName(const QString &filter);
     QString filterName() const;
@@ -53,4 +53,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif // FILTERNAMEDIALOG_H
+#endif // QFILTERNAMEDIALOG_H
diff --git a/src/assistant/help/qhelpfiltersettings.cpp b/src/assistant/help/qhelpfiltersettings.cpp
new file mode 100644
index 000000000..e9a1c3f4e
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettings.cpp
@@ -0,0 +1,170 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qhelpfiltersettings_p.h"
+#include "qhelpfilterdata.h"
+
+#include <QtCore/QMap>
+#include <QtHelp/QHelpFilterEngine>
+
+QT_BEGIN_NAMESPACE
+
+class QHelpFilterSettingsPrivate : public QSharedData
+{
+public:
+    QHelpFilterSettingsPrivate() = default;
+    QHelpFilterSettingsPrivate(const QHelpFilterSettingsPrivate &other) = default;
+    ~QHelpFilterSettingsPrivate() = default;
+
+    QMap<QString, QHelpFilterData> m_filterToData;
+    QString m_currentFilter;
+};
+
+QHelpFilterSettings::QHelpFilterSettings()
+    : d(new QHelpFilterSettingsPrivate)
+{
+}
+
+QHelpFilterSettings::QHelpFilterSettings(const QHelpFilterSettings &) = default;
+
+QHelpFilterSettings::QHelpFilterSettings(QHelpFilterSettings &&) = default;
+
+QHelpFilterSettings::~QHelpFilterSettings() = default;
+
+QHelpFilterSettings &QHelpFilterSettings::operator=(const QHelpFilterSettings &) = default;
+
+QHelpFilterSettings &QHelpFilterSettings::operator=(QHelpFilterSettings &&) = default;
+
+void QHelpFilterSettings::setFilter(const QString &filterName,
+                                    const QHelpFilterData &filterData)
+{
+    d->m_filterToData.insert(filterName, filterData);
+}
+
+void QHelpFilterSettings::removeFilter(const QString &filterName)
+{
+    d->m_filterToData.remove(filterName);
+}
+
+QStringList QHelpFilterSettings::filterNames() const
+{
+    return d->m_filterToData.keys();
+}
+
+QHelpFilterData QHelpFilterSettings::filterData(const QString &filterName) const
+{
+    return d->m_filterToData.value(filterName);
+}
+
+QMap<QString, QHelpFilterData> QHelpFilterSettings::filters() const
+{
+    return d->m_filterToData;
+}
+
+void QHelpFilterSettings::setCurrentFilter(const QString &filterName)
+{
+    d->m_currentFilter = filterName;
+}
+
+QString QHelpFilterSettings::currentFilter() const
+{
+    return d->m_currentFilter;
+}
+
+QHelpFilterSettings QHelpFilterSettings::readSettings(QHelpFilterEngine *filterEngine)
+{
+    QHelpFilterSettings filterSettings;
+
+    const QStringList allFilters = filterEngine->filters();
+    for (const QString &filter : allFilters)
+        filterSettings.setFilter(filter, filterEngine->filterData(filter));
+
+    filterSettings.setCurrentFilter(filterEngine->activeFilter());
+
+    return filterSettings;
+}
+
+static QMap<QString, QHelpFilterData> subtract(const QMap<QString, QHelpFilterData> &minuend,
+                                               const QMap<QString, QHelpFilterData> &subtrahend)
+{
+    QMap<QString, QHelpFilterData> result = minuend;
+
+    for (auto itSubtrahend = subtrahend.cbegin(); itSubtrahend != subtrahend.cend(); ++itSubtrahend) {
+        auto itResult = result.find(itSubtrahend.key());
+        if (itResult != result.end() && itSubtrahend.value() == itResult.value())
+            result.erase(itResult);
+    }
+
+    return result;
+}
+
+bool QHelpFilterSettings::applySettings(QHelpFilterEngine *filterEngine,
+                                        const QHelpFilterSettings &settings)
+{
+    bool changed = false;
+    const QHelpFilterSettings oldSettings = readSettings(filterEngine);
+
+    const QMap<QString, QHelpFilterData> filtersToRemove = subtract(
+                oldSettings.filters(),
+                settings.filters());
+    const QMap<QString, QHelpFilterData> filtersToAdd = subtract(
+                settings.filters(),
+                oldSettings.filters());
+
+    const QString &currentFilter = filterEngine->activeFilter();
+
+    for (const QString &filter : filtersToRemove.keys()) {
+        filterEngine->removeFilter(filter);
+        if (currentFilter == filter && !filtersToAdd.contains(filter))
+            filterEngine->setActiveFilter(QString());
+        changed = true;
+    }
+
+    for (auto it = filtersToAdd.cbegin(); it != filtersToAdd.cend(); ++it) {
+        filterEngine->setFilterData(it.key(), it.value());
+        changed = true;
+    }
+
+    if (changed)
+        filterEngine->setActiveFilter(settings.currentFilter());
+
+    return changed;
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpfiltersettings_p.h b/src/assistant/help/qhelpfiltersettings_p.h
new file mode 100644
index 000000000..50e30e492
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettings_p.h
@@ -0,0 +1,85 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QHELPFILTERSETTINGS_H
+#define QHELPFILTERSETTINGS_H
+
+#include <QtCore/QSharedDataPointer>
+
+QT_BEGIN_NAMESPACE
+
+template <class K, class T>
+class QMap;
+class QHelpFilterData;
+class QHelpFilterEngine;
+class QHelpFilterSettingsPrivate;
+
+class QHelpFilterSettings final
+{
+public:
+    QHelpFilterSettings();
+    QHelpFilterSettings(const QHelpFilterSettings &other);
+    QHelpFilterSettings(QHelpFilterSettings &&other);
+    ~QHelpFilterSettings();
+
+    QHelpFilterSettings &operator=(const QHelpFilterSettings &other);
+    QHelpFilterSettings &operator=(QHelpFilterSettings &&other);
+
+    void swap(QHelpFilterSettings &other) noexcept
+    { d.swap(other.d); }
+
+    void setFilter(const QString &filterName, const QHelpFilterData &filterData);
+    void removeFilter(const QString &filterName);
+    QStringList filterNames() const;
+    QHelpFilterData filterData(const QString &filterName) const;
+    QMap<QString, QHelpFilterData> filters() const;
+
+    void setCurrentFilter(const QString &filterName);
+    QString currentFilter() const;
+
+    static QHelpFilterSettings readSettings(QHelpFilterEngine *filterEngine);
+    static bool applySettings(QHelpFilterEngine *filterEngine, const QHelpFilterSettings &settings);
+
+private:
+    QSharedDataPointer<QHelpFilterSettingsPrivate> d;
+};
+
+QT_END_NAMESPACE
+
+#endif // QHELPFILTERSETTINGS_H
diff --git a/src/assistant/help/qhelpfiltersettingswidget.cpp b/src/assistant/help/qhelpfiltersettingswidget.cpp
new file mode 100644
index 000000000..15cc4f475
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettingswidget.cpp
@@ -0,0 +1,428 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qhelpfilterdata.h"
+#include "qhelpfiltersettings_p.h"
+#include "qhelpfiltersettingswidget.h"
+#include "ui_qhelpfiltersettingswidget.h"
+#include "qfilternamedialog_p.h"
+
+#include <QtWidgets/QMessageBox>
+#include <QtCore/QVersionNumber>
+
+QT_BEGIN_NAMESPACE
+
+static QStringList versionsToStringList(const QList<QVersionNumber> &versions)
+{
+    QStringList versionList;
+    for (const QVersionNumber &version : versions)
+        versionList.append(version.isNull() ? QString() : version.toString());
+    return versionList;
+}
+
+static QList<QVersionNumber> stringListToVersions(const QStringList &versionList)
+{
+    QList<QVersionNumber> versions;
+    for (const QString &versionString : versionList)
+        versions.append(QVersionNumber::fromString(versionString));
+    return versions;
+}
+
+class QHelpFilterSettingsWidgetPrivate
+{
+    QHelpFilterSettingsWidget *q_ptr;
+    Q_DECLARE_PUBLIC(QHelpFilterSettingsWidget)
+public:
+    QHelpFilterSettingsWidgetPrivate() = default;
+
+    QHelpFilterSettings filterSettings() const;
+    void setFilterSettings(const QHelpFilterSettings &settings);
+
+    void updateCurrentFilter();
+    void componentsChanged(const QStringList &components);
+    void versionsChanged(const QStringList &versions);
+    void addFilterClicked();
+    void renameFilterClicked();
+    void removeFilterClicked();
+    void addFilter(const QString &filterName,
+                   const QHelpFilterData &filterData = QHelpFilterData());
+    void removeFilter(const QString &filterName);
+    QString getUniqueFilterName(const QString &windowTitle,
+                                const QString &initialFilterName);
+    QString suggestedNewFilterName(const QString &initialFilterName) const;
+
+    QMap<QString, QListWidgetItem *> m_filterToItem;
+    QHash<QListWidgetItem *, QString> m_itemToFilter;
+
+    Ui::QHelpFilterSettingsWidget m_ui;
+    QStringList m_components;
+    QList<QVersionNumber> m_versions;
+    QHelpFilterSettings m_filterSettings;
+};
+
+void QHelpFilterSettingsWidgetPrivate::setFilterSettings(const QHelpFilterSettings &settings)
+{
+    QString currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty()) {
+        if (!m_filterSettings.currentFilter().isEmpty())
+            currentFilter = m_filterSettings.currentFilter();
+        else
+            currentFilter = settings.currentFilter();
+    }
+
+    m_filterSettings = settings;
+
+    m_ui.filterWidget->clear();
+    m_ui.componentWidget->clear();
+    m_ui.versionWidget->clear();
+    m_itemToFilter.clear();
+    m_filterToItem.clear();
+
+    for (const QString &filterName : m_filterSettings.filterNames()) {
+        QListWidgetItem *item = new QListWidgetItem(filterName);
+        m_ui.filterWidget->addItem(item);
+        m_itemToFilter.insert(item, filterName);
+        m_filterToItem.insert(filterName, item);
+        if (filterName == currentFilter)
+            m_ui.filterWidget->setCurrentItem(item);
+    }
+
+    if (!m_ui.filterWidget->currentItem() && !m_filterToItem.isEmpty())
+        m_ui.filterWidget->setCurrentItem(m_filterToItem.first());
+
+    updateCurrentFilter();
+}
+
+QHelpFilterSettings QHelpFilterSettingsWidgetPrivate::filterSettings() const
+{
+    return m_filterSettings;
+}
+
+void QHelpFilterSettingsWidgetPrivate::updateCurrentFilter()
+{
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+
+    const bool filterSelected = !currentFilter.isEmpty();
+    m_ui.componentWidget->setEnabled(filterSelected);
+    m_ui.versionWidget->setEnabled(filterSelected);
+    m_ui.renameButton->setEnabled(filterSelected);
+    m_ui.removeButton->setEnabled(filterSelected);
+
+    m_ui.componentWidget->setOptions(m_components,
+            m_filterSettings.filterData(currentFilter).components());
+    m_ui.versionWidget->setOptions(versionsToStringList(m_versions),
+            versionsToStringList(m_filterSettings.filterData(currentFilter).versions()));
+}
+
+void QHelpFilterSettingsWidgetPrivate::componentsChanged(const QStringList &components)
+{
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    QHelpFilterData filterData = m_filterSettings.filterData(currentFilter);
+    filterData.setComponents(components);
+    m_filterSettings.setFilter(currentFilter, filterData);
+}
+
+void QHelpFilterSettingsWidgetPrivate::versionsChanged(const QStringList &versions)
+{
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    QHelpFilterData filterData = m_filterSettings.filterData(currentFilter);
+    filterData.setVersions(stringListToVersions(versions));
+    m_filterSettings.setFilter(currentFilter, filterData);
+}
+
+void QHelpFilterSettingsWidgetPrivate::addFilterClicked()
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    const QString newFilterName = getUniqueFilterName(q->tr("Add Filter"),
+                                  suggestedNewFilterName(q->tr("New Filter")));
+    if (newFilterName.isEmpty())
+        return;
+
+    addFilter(newFilterName);
+}
+
+void QHelpFilterSettingsWidgetPrivate::renameFilterClicked()
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    const QString newFilterName = getUniqueFilterName(q->tr("Rename Filter"), currentFilter);
+    if (newFilterName.isEmpty())
+        return;
+
+    const QHelpFilterData oldFilterData = m_filterSettings.filterData(currentFilter);
+    removeFilter(currentFilter);
+    addFilter(newFilterName, oldFilterData);
+
+    if (m_filterSettings.currentFilter() == currentFilter)
+        m_filterSettings.setCurrentFilter(newFilterName);
+}
+
+void QHelpFilterSettingsWidgetPrivate::removeFilterClicked()
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    const QString &currentFilter = m_itemToFilter.value(m_ui.filterWidget->currentItem());
+    if (currentFilter.isEmpty())
+        return;
+
+    if (QMessageBox::question(q, q->tr("Remove Filter"),
+                              q->tr("Are you sure you want to remove the \"%1\" filter?")
+                              .arg(currentFilter),
+                              QMessageBox::Yes | QMessageBox::No)
+            != QMessageBox::Yes) {
+        return;
+    }
+
+    removeFilter(currentFilter);
+
+    if (m_filterSettings.currentFilter() == currentFilter)
+        m_filterSettings.setCurrentFilter(QString());
+}
+
+void QHelpFilterSettingsWidgetPrivate::addFilter(const QString &filterName,
+                                                 const QHelpFilterData &filterData)
+{
+    QListWidgetItem *item = new QListWidgetItem(filterName);
+    m_filterSettings.setFilter(filterName, filterData);
+    m_filterToItem.insert(filterName, item);
+    m_itemToFilter.insert(item, filterName);
+    m_ui.filterWidget->insertItem(m_filterToItem.keys().indexOf(filterName), item);
+
+    m_ui.filterWidget->setCurrentItem(item);
+    updateCurrentFilter();
+}
+
+void QHelpFilterSettingsWidgetPrivate::removeFilter(const QString &filterName)
+{
+    QListWidgetItem *item = m_filterToItem.value(filterName);
+    m_itemToFilter.remove(item);
+    m_filterToItem.remove(filterName);
+    delete item;
+
+    m_filterSettings.removeFilter(filterName);
+}
+
+QString QHelpFilterSettingsWidgetPrivate::getUniqueFilterName(const QString &windowTitle,
+                                                              const QString &initialFilterName)
+{
+    Q_Q(QHelpFilterSettingsWidget);
+
+    QString newFilterName = initialFilterName;
+    while (1) {
+        QFilterNameDialog dialog(q);
+        dialog.setWindowTitle(windowTitle);
+        dialog.setFilterName(newFilterName);
+        if (dialog.exec() == QDialog::Rejected)
+            return QString();
+
+        newFilterName = dialog.filterName();
+        if (!m_filterToItem.contains(newFilterName))
+            break;
+
+        if (QMessageBox::warning(q, q->tr("Filter Exists"),
+                                 q->tr("The filter \"%1\" already exists.")
+                                 .arg(newFilterName),
+                                 QMessageBox::Retry | QMessageBox::Cancel)
+                == QMessageBox::Cancel) {
+            return QString();
+        }
+    }
+
+    return newFilterName;
+}
+
+QString QHelpFilterSettingsWidgetPrivate::suggestedNewFilterName(const QString &initialFilterName) const
+{
+    QString newFilterName = initialFilterName;
+
+    int counter = 1;
+    while (m_filterToItem.contains(newFilterName)) {
+        newFilterName = initialFilterName + QLatin1Char(' ')
+                + QString::number(++counter);
+    }
+
+    return newFilterName;
+}
+
+/*!
+    \class QHelpFilterSettingsWidget
+    \inmodule QtHelp
+    \since 5.15
+    \brief The QHelpFilterSettingsWidget class provides a widget that allows
+    for creating, editing and removing filters.
+
+    The instance of QHelpFilterSettingsWidget may be a part of
+    a preferences dialog. Before showing the dialog, \l setAvailableComponents()
+    and \l setAvailableVersions() should be called, otherwise the filter
+    settings widget will only offer a creation of empty filters,
+    which wouldn't be useful. In addition, \l readSettings should also
+    be called to fill up the filter settings widget with the list of filters
+    already stored in the filter engine. The creation of new filters,
+    modifications to existing filters and removal of unneeded filters are
+    handled by the widget automatically. If you want to store the current
+    state of the widget and apply it to the filter engine e.g. after
+    the user clicked the apply button - call \l applySettings().
+*/
+
+/*!
+    Constructs a filter settings widget with \a parent as parent widget.
+*/
+QHelpFilterSettingsWidget::QHelpFilterSettingsWidget(QWidget *parent)
+    : QWidget(parent)
+    , d_ptr(new QHelpFilterSettingsWidgetPrivate())
+{
+    Q_D(QHelpFilterSettingsWidget);
+    d->q_ptr = this;
+    d->m_ui.setupUi(this);
+
+    // TODO: make resources configurable
+    QString resourcePath = QLatin1String(":/qt-project.org/assistant/images/");
+#ifdef Q_OS_MACOS
+    resourcePath.append(QLatin1String("mac"));
+#else
+    resourcePath.append(QLatin1String("win"));
+#endif
+    d->m_ui.addButton->setIcon(QIcon(resourcePath + QLatin1String("/plus.png")));
+    d->m_ui.removeButton->setIcon(QIcon(resourcePath + QLatin1String("/minus.png")));
+
+    connect(d->m_ui.componentWidget, &QOptionsWidget::optionSelectionChanged,
+            [this](const QStringList &options) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->componentsChanged(options);
+    });
+    connect(d->m_ui.versionWidget, &QOptionsWidget::optionSelectionChanged,
+            [this](const QStringList &options) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->versionsChanged(options);
+    });
+    connect(d->m_ui.filterWidget, &QListWidget::currentItemChanged,
+            this, [this](QListWidgetItem *) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->updateCurrentFilter();
+    });
+    connect(d->m_ui.filterWidget, &QListWidget::itemDoubleClicked,
+            [this](QListWidgetItem *) {
+        Q_D(QHelpFilterSettingsWidget);
+        d->renameFilterClicked();
+    });
+
+    // TODO: repeat these actions on context menu
+    connect(d->m_ui.addButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(QHelpFilterSettingsWidget);
+        d->addFilterClicked();
+    });
+    connect(d->m_ui.renameButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(QHelpFilterSettingsWidget);
+        d->renameFilterClicked();
+    });
+    connect(d->m_ui.removeButton, &QAbstractButton::clicked,
+            [this]() {
+        Q_D(QHelpFilterSettingsWidget);
+        d->removeFilterClicked();
+    });
+
+    d->m_ui.componentWidget->setNoOptionText(tr("No Component"));
+    d->m_ui.componentWidget->setInvalidOptionText(tr("Invalid Component"));
+    d->m_ui.versionWidget->setNoOptionText(tr("No Version"));
+    d->m_ui.versionWidget->setInvalidOptionText(tr("Invalid Version"));
+}
+
+/*!
+    Destroys the filter settings widget.
+*/
+QHelpFilterSettingsWidget::~QHelpFilterSettingsWidget() = default;
+
+/*!
+    Sets the list of all available components to \a components.
+    \sa QHelpFilterEngine::availableComponents()
+*/
+void QHelpFilterSettingsWidget::setAvailableComponents(const QStringList &components)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    d->m_components = components;
+    d->updateCurrentFilter();
+}
+
+/*!
+    Sets the list of all available version numbers to \a versions.
+    \sa QHelpFilterEngine::availableVersions()
+*/
+void QHelpFilterSettingsWidget::setAvailableVersions(const QList<QVersionNumber> &versions)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    d->m_versions = versions;
+    d->updateCurrentFilter();
+}
+
+/*!
+    Reads the filter settings stored inside \a filterEngine and sets up
+    this filter settings widget accordingly.
+*/
+void QHelpFilterSettingsWidget::readSettings(QHelpFilterEngine *filterEngine)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    const QHelpFilterSettings settings = QHelpFilterSettings::readSettings(filterEngine);
+    d->setFilterSettings(settings);
+}
+
+/*!
+    Writes the filter settings, currently presented in this filter settings
+    widget, to the \a filterEngine. The old settings stored in the filter
+    engine will be overwritten.
+*/
+bool QHelpFilterSettingsWidget::applySettings(QHelpFilterEngine *filterEngine)
+{
+    Q_D(QHelpFilterSettingsWidget);
+    return QHelpFilterSettings::applySettings(filterEngine, d->filterSettings());
+}
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpfiltersettingswidget.h b/src/assistant/help/qhelpfiltersettingswidget.h
new file mode 100644
index 000000000..1b6606054
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettingswidget.h
@@ -0,0 +1,78 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt Assistant of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QHELPFILTERSETTINGSWIDGET_H
+#define QHELPFILTERSETTINGSWIDGET_H
+
+#include <QtHelp/qhelp_global.h>
+
+#include <QtWidgets/QWidget>
+
+QT_BEGIN_NAMESPACE
+
+class QVersionNumber;
+
+class QHelpFilterEngine;
+class QHelpFilterSettingsWidgetPrivate;
+
+class QHELP_EXPORT QHelpFilterSettingsWidget : public QWidget
+{
+    Q_OBJECT
+public:
+    QHelpFilterSettingsWidget(QWidget *parent);
+
+    ~QHelpFilterSettingsWidget();
+
+    void setAvailableComponents(const QStringList &components);
+    void setAvailableVersions(const QList<QVersionNumber> &versions);
+
+    // TODO: filterEngine may be moved to c'tor or to setFilterEngine() setter
+    void readSettings(QHelpFilterEngine *filterEngine);
+    bool applySettings(QHelpFilterEngine *filterEngine);
+
+private:
+    QScopedPointer<class QHelpFilterSettingsWidgetPrivate> d_ptr;
+    Q_DECLARE_PRIVATE(QHelpFilterSettingsWidget)
+    Q_DISABLE_COPY_MOVE(QHelpFilterSettingsWidget)
+};
+
+QT_END_NAMESPACE
+
+#endif
+
diff --git a/src/assistant/help/qhelpfiltersettingswidget.ui b/src/assistant/help/qhelpfiltersettingswidget.ui
new file mode 100644
index 000000000..7e16e3f7b
--- /dev/null
+++ b/src/assistant/help/qhelpfiltersettingswidget.ui
@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>QHelpFilterSettingsWidget</class>
+ <widget class="QWidget" name="QHelpFilterSettingsWidget">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>347</width>
+    <height>127</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QGridLayout" name="gridLayout">
+   <item row="0" column="0" colspan="3">
+    <widget class="QLabel" name="filterLabel">
+     <property name="text">
+      <string>Filter</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="3">
+    <widget class="QLabel" name="componentsLabel">
+     <property name="frameShape">
+      <enum>QFrame::NoFrame</enum>
+     </property>
+     <property name="text">
+      <string>Components</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="4">
+    <widget class="QLabel" name="versionsLabel">
+     <property name="text">
+      <string>Versions</string>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="0" colspan="3">
+    <widget class="QListWidget" name="filterWidget"/>
+   </item>
+   <item row="1" column="3" rowspan="2">
+    <widget class="QOptionsWidget" name="componentWidget" native="true"/>
+   </item>
+   <item row="1" column="4" rowspan="2">
+    <widget class="QOptionsWidget" name="versionWidget" native="true"/>
+   </item>
+   <item row="2" column="0">
+    <widget class="QToolButton" name="addButton">
+     <property name="text">
+      <string>Add...</string>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="1">
+    <widget class="QToolButton" name="renameButton">
+     <property name="text">
+      <string>Rename...</string>
+     </property>
+    </widget>
+   </item>
+   <item row="2" column="2">
+    <widget class="QToolButton" name="removeButton">
+     <property name="text">
+      <string>Remove</string>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QOptionsWidget</class>
+   <extends>QWidget</extends>
+   <header>qoptionswidget_p.h</header>
+   <container>1</container>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/src/assistant/assistant/optionswidget.cpp b/src/assistant/help/qoptionswidget.cpp
index bc089c5bf..21fdfe07a 100644
--- a/src/assistant/assistant/optionswidget.cpp
+++ b/src/assistant/help/qoptionswidget.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Assistant of the Qt Toolkit.
@@ -26,20 +26,17 @@
 **
 ****************************************************************************/
 
-#include "optionswidget.h"
+#include "qoptionswidget_p.h"
 
 #include <QtWidgets/QComboBox>
 #include <QtWidgets/QItemDelegate>
 #include <QtWidgets/QListWidget>
 #include <QtWidgets/QVBoxLayout>
 
-#include <algorithm>
-
 QT_BEGIN_NAMESPACE
 
 class ListWidgetDelegate : public QItemDelegate
 {
-//    Q_OBJECT not needed
 public:
     ListWidgetDelegate(QWidget *w) : QItemDelegate(w), m_widget(w) {}
 
@@ -87,9 +84,7 @@ static QStringList subtract(const QStringList &minuend, const QStringList &subtr
     return result;
 }
 
-/////////////////
-
-OptionsWidget::OptionsWidget(QWidget *parent)
+QOptionsWidget::QOptionsWidget(QWidget *parent)
     : QWidget(parent)
     , m_noOptionText(tr("No Option"))
     , m_invalidOptionText(tr("Invalid Option"))
@@ -100,16 +95,16 @@ OptionsWidget::OptionsWidget(QWidget *parent)
     layout->addWidget(m_listWidget);
     layout->setContentsMargins(QMargins());
 
-    connect(m_listWidget, &QListWidget::itemChanged, this, &OptionsWidget::itemChanged);
+    connect(m_listWidget, &QListWidget::itemChanged, this, &QOptionsWidget::itemChanged);
 }
 
-void OptionsWidget::clear()
+void QOptionsWidget::clear()
 {
     setOptions(QStringList(), QStringList());
 }
 
-void OptionsWidget::setOptions(const QStringList &validOptions,
-                               const QStringList &selectedOptions)
+void QOptionsWidget::setOptions(const QStringList &validOptions,
+                                const QStringList &selectedOptions)
 {
     m_listWidget->clear();
     m_optionToItem.clear();
@@ -145,17 +140,17 @@ void OptionsWidget::setOptions(const QStringList &validOptions,
     }
 }
 
-QStringList OptionsWidget::validOptions() const
+QStringList QOptionsWidget::validOptions() const
 {
     return m_validOptions;
 }
 
-QStringList OptionsWidget::selectedOptions() const
+QStringList QOptionsWidget::selectedOptions() const
 {
     return m_selectedOptions;
 }
 
-void OptionsWidget::setNoOptionText(const QString &text)
+void QOptionsWidget::setNoOptionText(const QString &text)
 {
     if (m_noOptionText == text)
         return;
@@ -171,7 +166,7 @@ void OptionsWidget::setNoOptionText(const QString &text)
     }
 }
 
-void OptionsWidget::setInvalidOptionText(const QString &text)
+void QOptionsWidget::setInvalidOptionText(const QString &text)
 {
     if (m_invalidOptionText == text)
         return;
@@ -183,7 +178,7 @@ void OptionsWidget::setInvalidOptionText(const QString &text)
         m_optionToItem.value(option)->setText(optionText(option, false));
 }
 
-QString OptionsWidget::optionText(const QString &optionName, bool valid) const
+QString QOptionsWidget::optionText(const QString &optionName, bool valid) const
 {
     QString text = optionName;
     if (optionName.isEmpty())
@@ -193,7 +188,7 @@ QString OptionsWidget::optionText(const QString &optionName, bool valid) const
     return text;
 }
 
-QListWidgetItem *OptionsWidget::appendItem(const QString &optionName, bool valid, bool selected)
+QListWidgetItem *QOptionsWidget::appendItem(const QString &optionName, bool valid, bool selected)
 {
     QListWidgetItem *optionItem = new QListWidgetItem(optionText(optionName, valid), m_listWidget);
     optionItem->setCheckState(selected ? Qt::Checked : Qt::Unchecked);
@@ -203,14 +198,14 @@ QListWidgetItem *OptionsWidget::appendItem(const QString &optionName, bool valid
     return optionItem;
 }
 
-void OptionsWidget::appendSeparator()
+void QOptionsWidget::appendSeparator()
 {
     QListWidgetItem *separatorItem = new QListWidgetItem(m_listWidget);
     ListWidgetDelegate::setSeparator(separatorItem);
     m_listWidget->insertItem(m_listWidget->count(), separatorItem);
 }
 
-void OptionsWidget::itemChanged(QListWidgetItem *item)
+void QOptionsWidget::itemChanged(QListWidgetItem *item)
 {
     const auto it = m_itemToOption.constFind(item);
     if (it == m_itemToOption.constEnd())
diff --git a/src/assistant/assistant/optionswidget.h b/src/assistant/help/qoptionswidget_p.h
index 52c876bad..ff075e464 100644
--- a/src/assistant/assistant/optionswidget.h
+++ b/src/assistant/help/qoptionswidget_p.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Assistant of the Qt Toolkit.
@@ -26,8 +26,8 @@
 **
 ****************************************************************************/
 
-#ifndef OPTIONSWIDGET_H
-#define OPTIONSWIDGET_H
+#ifndef QOPTIONSWIDGET_H
+#define QOPTIONSWIDGET_H
 
 #include <QtWidgets/QWidget>
 #include <QtCore/QMap>
@@ -37,11 +37,11 @@ QT_BEGIN_NAMESPACE
 class QListWidget;
 class QListWidgetItem;
 
-class OptionsWidget : public QWidget
+class QOptionsWidget : public QWidget
 {
     Q_OBJECT
 public:
-    OptionsWidget(QWidget *parent = nullptr);
+    QOptionsWidget(QWidget *parent = nullptr);
 
     void clear();
     void setOptions(const QStringList &validOptions,