Problem:    Crash when using null partial in filter().
Solution:   Fix crash.  Add more tests. (Yegappan Lakshmanan, closes #5976)

Problem:    Tests fail when the float feature is disabled.
Solution:   Skip tests that don't work without float support.

Problem:    Using null object with execute() has strange effects.
Solution:   Give an error message ofr Job and Channel.

Problem:    Cannot build with +popupwin but without +quickfix. (John Marriott)
Solution:   Adjust #ifdefs.

Problem:    FEAT_TEXT_PROP is a confusing name.
Solution:   Use FEAT_PROP_POPUP. (Naruhiko Nishino, closes #5291)

Problem:    Ruler is not updated if win_execute() moves cursor.
Solution:   Update the status line. (closes #5022)

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.

Problem:    Win_execute() does not work in other tab. (Rick Howe)
Solution:   Take care of the tab. (closes #4792)

Problem:    Win_execute() test fails.
Solution:   Adjust the expected error number.  Move to popup test.

Problem:    Win_execute() is not implemented yet.
Solution:   Implement it.