Alt shortcut for activating menu entries not working

[antoine]

When using global menu with Qt application, the "alt" key shortcut, that usually allows activating menu entries does not work. For instance, in Qt-creator, typing Alt+F followed by x should open the "File" menu (Alt+F) and exit the program (x activates the "exit" entry).
However, when typing Alt+F, the File menu is not opened (when pressing the Alt-key, the menu is displayed, but pressing F does not activate the "File" menu).

I have encountered the problem with qt creator, and other qt applications build by myself. The problem occurs both with qt4 and qt5 applications (I have tried recompiling one of my applications with qt4 to check whether it solved my issue).

I have encountered this issue with ubuntu 13.04 amd64.