Hello wolfmandim, check it in Safe Mode, in Safe Mode window select "Start in Safe Mode" and see if this happen again, if not then see: Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

(If the problem does not happen in Safe Mode, it is most likely because of an extension, theme or hardware acceleration).

thank you

It seems to work fine in Safe Mode. I removed and reinstalled Firefox 18 but still have the same effects. What can I do next?

If the problem does not happen in Safe Mode, it is most likely because of an extension, theme or hardware acceleration, as first step try to Turn off hardware acceleration and check it again (in safe mode hardware acceleration is disable), if doesn't solve the issue then Disable all extensions and if the problem no longer occurs with all extensions disabled, one of your extensions was causing it. To find the extension that was causing your problem see : Test for faulty extensions.

probably an extension is the problem

see also : Switch to the default theme if the above doesn't work.

thank you

I tried every one of them, still no success. I would have thought my mouse is at fault, but it works with other browsers..... Any other suggestions?

UPDATE: It appears that the latest Logitech Setpoint 6.51 x64 drivers are causing the problem. As soon as I uninstalled the software everything works just fine!

Hello wolfmandim, i'm happy you find it and solve your issue. Mark solved YOUR reply with solution to help others with same problem.

thanks

As with others, I have downloaded the lastest updates to Firefox (as suggested by Firefox, I was not looking for them), and now the mouse does not work at all. That means that I cannot open the Options tab, I cannot do anything since the mouse does absolutely nothing at all in Firefox. In order to stop the program, I have to go to the Task Manager and have it close the program.