Comment 2 for bug 1077395

Exactly the same problem/behaviour here:
Sometimes (actually quite often - at one still undefinable point during every session) LibreOffice refuses to open any new dialogue. It won't even close anymore by means of the menu (File -> Quit) - just by closing the window.
Luckily saving the document by double-clicking the small icon in LibreOffice's status bar still works - otherwise this would be even more severe.
Closing and restarting convinces LibreOfice to work normally again for some time - until the same problem reappears.

Running Ubuntu 12.10
LibreOffice Version 3.6.2.2 (Build ID: 360m1(Build:2))