Do you notice this behavior on any specific websites? Does it still occur after disabling any Firefox add-ons you have installed?

Annnnd I figured it out. It was Yes Popups, which apparently affects opening links that would normally open in a new tab. I can fix it now. Thanks for helping me solve my stupid problem haha.

I am having this problem too! After a while some firefox buttons will stop responding to left mouse clicks. The menus and tabs respond but everything else (minimize, maximize, close) will not. Pop up menus like the download manager will not respond either. I can open the download manager through the menu but I cannot close it, clear the list, or click downloads. The only way to close firefox is through file >>exit but if there are mutiple tabs open I cannot click the save and quit, etc. buttons and I have to close firefox through the task manager. The problem occurs randomly. Sometimes it will not happen at all and other times it will happen immediately upon starting FF. I have tried disabling all of the plugins and extensions, reinstalling various versions of FF, and using new profile, but none of these things have helped. This is only happening in FF; no other programs do this.

OK, I have this problem too. 10-15 seconds after opening Firefox I lose the ability to left click almost anything - links, 'accept' 'cancel' or almost anything that needs clicking.

And at the same time my Chrome web browser stopped allowing me to switch tabs - it simply closes any tab I click!

coincidence? I don't think so.

I started having this problem today. It is being caused by an add on. When I updated my Zone Alarm Free Firewall, it automatically downloaded the Zone Alarm Free Security Toolbar, even though I unchecked it during installation/upgrade of Zone Alarm. The problem ceased when I started Mozilla Firefox in safe mode, but this did not tell me which add on was causing the problem. Since it was a left click problem on the tab bar only, I tried shutting on and off tab add ons to no avail. When I shut off ZAF and put back Windows 7 Firewall the problem still persisted. I noticed that there was an extra blank space between one of my toolbars and the tabs (I do not keep them on top but in the old position). I was about to uninstall Zone Alarm Free Firewall, and reinstall previous version when I saw in add ons that ZA Free toolbar along with ZA Free in Revo Uninstaller. I went back to add ons and sure enough, even though the toolbar runs w/permission in IE9, it is usually disabled in Firefox because it is "incompatible." When upgraded Zone Alarm Free this morning, it was reinstalled in Firefox but Firefox DID NOT disable it as incompatible. It is incompatible. I not only disabled it, but I uninstalled it completely w/Revo Uninstaller because I never use IE9 and it has been incompatible in Firefox upgrades since before the rapid release cycle started in 2011. I hope this helps a few other people. I am getting tired of Mozilla Firefox Help rejecting my user name/password combo all the time, every time I use it even though Last Pass remembers it, Firefox help does not and I keep having to reset my password every time, which then the reset password does not work right after the reset. It's why I don't post my resolved issues here anymore.