qt menu item does not show

I'm writing a window manager and I'm stuck with a problem on Qt4 menu bar elements.

When I first click on the menu item, it shows correctly, then I close it and try to open it again but it does not show anymore. If I try to open another menu item, it works for the first time and then that item cannot be shown again too. I tried a lot of tricks like c开发者_运维问答hanging focus, resizing or moving the window, but it does not work.

I tried with a couple of Qt applications (smplayer and QtOctave) and all have the same issue on the menu bar. I also tested GIMP and xfe (which run on gtk, just to countercheck) and their menus work correctly. I did not test any Qt3 application yet, but I guess they behave the same way.

Note: It gives me the same issue with Qt4 context menus.

Note: The menu itself works, but it's invisible after the first time..