Although, it looks like your compiz process may have crashed. When the problem occurs, could you please log into a VT (Ctrl+Alt+F1) and run "pidof compiz"? Do you get a result?
If not, then compiz/unity has crashed. In that case my response would be... https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment
Although, it looks like your compiz process may have crashed. When the problem occurs, could you please log into a VT (Ctrl+Alt+F1) and run "pidof compiz"? Do you get a result?
If not, then compiz/unity has crashed. In that case my response would be... /wiki.ubuntu. com/Bugs/ Responses# Missing_ a_crash_ report_ or_having_ a_.crash_ attachment
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