I see this in Qt Creator as well as in a self-compiled LyX on Ubuntu 14.04. It might be useful to note that in the LyX case, one can get the menu bar back by executing the following command (in LyX's internal language)
ui-toggle menubar
Removing appmenu-qt5 solved the problem in both cases for me.
I see this in Qt Creator as well as in a self-compiled LyX on Ubuntu 14.04. It might be useful to note that in the LyX case, one can get the menu bar back by executing the following command (in LyX's internal language)
ui-toggle menubar
Removing appmenu-qt5 solved the problem in both cases for me.