If you’re running the nightly builds of Mozilla and it keeps crashing on exit, you’ve probably run into bug 182803 — “Mozilla crashes on exit if it connects to a SSL server” (either that or bug 156940, as both have over seven dupes).
And, I suppose your right-click context menus occasionally appear in weird places? Yeah, that’s bug 185107 — “Popup menu after right-click inside an iFrame is in wrong place”.