Drop down boxes are empty but clicking in it still works, same with right clicking the mouose.
When I click on the File, Edit... buttons the drop down box appears and is empty. I can guess where something should be and click on it and I'll get a reaction but I don't always get it right. When I Right Click on the mouse to copy and paste I get the same thing.
Wšě wotmołwy (2)
There's a couple of slightly incompatible add-ons that can cause that, you need to troubleshoot to discover the cause.
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes
I changed the theme back to the default and it worked for about a day. It then started acting up a few times a day and now it's doing it all the time again.