1 files changed, 3 insertions, 4 deletions
diff --git a/glib/glibmm/interface.cc b/glib/glibmm/interface.cc
index d13c5d8a..793e767a 100644
--- a/glib/glibmm/interface.cc
+++ b/glib/glibmm/interface.cc
@@ -95,10 +95,9 @@ Interface::Interface(const Interface_Class& interface_class)
     }
     else // gobject_ == nullptr
     {
-      // The GObject is not instantiated yet. Add to the custom_interface_classes
-      // and add the interface in the Glib::Object constructor.
-      std::lock_guard<std::mutex> lock(extra_object_base_data_mutex);
-      extra_object_base_data[this].custom_interface_classes.emplace_back(&interface_class);
+      // The GObject is not instantiated yet. Add to the stored custom interface
+      // classes, and add the interface to the GType in the Glib::Object constructor.
+      add_custom_interface_class(&interface_class);
     }
   }
 }