Michel,

had to restart machine about an H ago while FF was still running. Previously the FF ability to recreate all pages available before forced shutdown worked for UT as well, today the interface was garbled (most buttons on top not visible, some shifted "new" for instance )
Did not make a screen shot - sorry, surfing away and to UT again fixed it easily.
As you are currently reworking, test for this behaviour later when most of your changes are done, as it is not a big inconvenience - but put it on the list and the mental map - dunno what you are doing, but if it involves caching, thinking of such scenarios early is better than late ;-)