Ask HN: Firefox Right-click Bug?

I'm losing it here - this computer is going out the window soon. For the past few weeks Firefox began acting extremely strange/annoying with right clicks. Upon clicking, something different happens each time (basically it automatically chooses something off the right-click menu). I'll either get the menu, the page direction switched, a save file dialog, a highlight terms dialog, etc etc. I googled and read a ton of people complaining but couldn't find a fix. Anyone know of one???!

(extensions enabled: search status, firebug) (OS: Ubuntu 8.04, FF 3.0.3)