Comment 5 for bug 723463

So the crash itself is due to GtkMenuItems created in entry_added() in indicator-applet hanging around after their IndicatorObjectEntry objects have gone. When they are activated, they start making function calls with the obsolete entry object and end up causing a crash.

This is borne out by the duplicates, which mention menu items sticking around from other applications. I haven't figured out why that happens yet, but am looking.