Yesterday my Firefox right click suddenly stopped working, I couldn’t right click on any HTML pages, after Googling for a while, I realized that it was caused by a add-on I installed lately. It’s Yahoo! Toolbar. After going to Tools > Add-ons, and disable the Yahoo! Toolbar, my right click is back!
Another add-on that causes this issue is AVG SafeSearch. Have it disabled too if you want the right click. :)
Hope this helps. :)
