Currently I experienced a "focus" problem when an opened menu was overlapping the menu bar. I was not able to navigate to a submenu item because the menu bar below was still active and apparently of the same or higher priority as the submenu. Whenever I tried to navigate to one of the submenu items and hovering over one of the main menu bar items below, the submenu closes. However, it seems there is no, or no proper, priority system controlling the behaviour of the overlapping menus and submenus.
To recreate this, for example, go to Game Logic UI preset and slide the horizontal subdivision of the window arrangement somewhat over the middle of the screen, so that the lower menu bars of the upper windows are above the horizontal middle line of the screen.
Navigate to the Text Editor Window and to the menu bar item Templates > Python > . The appaering largish 2nd submenu folds out to the left and downwards so that it is overlapping the main menu bar. If not try to modify the Window arrangemetent until it does.
If you try to navigate to one of the submenu items you may see - it's not working properly.