Pressing the center mouse wheel no longer opens a link in a new tab. I tried disabling all add-ons, the problem still exists. I tried upgrading my mouse driver, it was already up to date. I already tried all the advice from this older question: http://support.mozilla.org/en-US/questions/783155?s=mouse+scroll+wheel+open+new+tab&r=0&as=s Firefox 14.0.1 on Windows 7. I use a Case Logic wireless mouse. There was a recent Windows update. The open in new tab ability disappeared after that update, but not immediately after.