[ ] For XDG_CURRENT_DESKTOP=KDE keep the use of KFileWidget
[ ] For XDG_CURRENT_DESKTOP!=KDE (e.g. XFCE) use the new Kexi's simplified file chooser
[ ] Add setting to force the use of KFileWidget even for XDG_CURRENT_DESKTOP!=KDE or Kexi's simplified file chooser for XDG_CURRENT_DESKTOP=KDE. Default value should be as described above.