Does somebody know some code to open the menubar automatically?
Or a way to update and repaint an open menubar?

I could implement a qpushbutton into the menu which lets the menu open when pressed and it should change some actions from the menu. It all does what I want but the result can only be seen by closing and reopen the menu again. I also tried to update and repaint parent widgets with no success.
In qt desktop version it is working

[edit]: So it looks like that this menu belongs to the WM, so I had to make a workaround with X11.