Comment 8 for bug 758613

I figured out the issue is 100% reproducible if you open an .odt which contains some java macros and if your security level is not set at the minimum :

in this case, a popup window appears asking whether you want to use the macros (or to warn you that macros are disabled) and consequently, the global menu is not visible (if the window is set to fullscreen, you can't even quit from fullscreen !)

If macros are disabled, the issue doesn't occur. (so I set a whitelist not to be bothered)