Yesterday my Firefox suddenly started showing strange boxes over various parts of every web page. For example, there are black boxes over the scroll bar. When viewing Facebook, there are little squares (black, grey, white) over the scroll bar, the little IM boxes at the bottom of the screen (the ones currently in use), etc. It seems a little better ont he Mozilla Support forum, but not at the bottom of the screen or on the Scroll bar. For the most part I can see most parts of every webpage. The scroll bar still works fine, as does IMing on FB, but the little boxes blink and are very annoying. So far I've tried to restart Firefox, checked to see if it's updated, but alas it's all as it should be. This is not happen when I use MS Word or Powerpoint, Safari, iTunes, other apps. Only with Firefox so I know it's a Firefox issue. I Have a Macbook Pro 13 inch mid-2010 2.4 GhZ Intel Core Duo processor 4 GB. Running Mac OSX Yosemite. I've also uploaded an image. It's of the scroll bar on the edge of the FB page. I can try to get others if you want to see more examples. The squares tend to flash and change shape, so it's hard to get a good screen capture. Thanks in advance for you help. JDClevergirl.