If i try to add a QWidget to the central widget of the ribbon style the widget
and all components of them are not displayed. This works on a normal QMainwindow.
I'm using a qt ui formular class.
The solution is to include the ui_... of the widget an initialize the ui form
with the setupUI command; btw the construtor of the class calls the setupUI
when I create the widget object but without any effect.
This should work without the extra call of setupUI or call them twice.