setting videowidget to normal after setting to fullscreen

setting videowidget to fullscreen works fine but returning back from fullscreen to normal is not working as expected and opens a new window out the layout and not attached to main widget but still remains a child of central widget.

the scribed problem occurs when using video widget as Qt's media player "setVideoOutput" AND/OR Gstreamer's "GST_VIDEO_OVERLAY".

note: using video output for A single video widget, effects all video widgets with the same problem even though they have no video output.

note: in windows platform the problem doesn't exist.