I didn't do anything with a bluetooth mouse, but it's happening to me, too. I've attached a crash report.
** Attachment added: "Crash report" http://librarian.launchpad.net/5176434/_usr_bin_mono.1000.crash -- Crash on startup https://launchpad.net/bugs/73277 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs