Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. Is the problem still there?

As I wrote above (In "safe mode" the problems don't exist.) in "safe mode" everything works fine.

It could be the work of one of your add-ons. Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control>(Mac=<Command>)<Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is detective.

Hi I have only 2 extensions and they are both disabled.

Type about:addons<enter> in the address bar to open the Add-ons Manager. Hot key; <Control>(Mac=<Command>) <Shift> A)

On the left side of the page, select Appearance. Then select Default.

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Restart Firefox. Are there any problems?

Thanks a lot - it seems like this was the solution! I found this solution already in another post and thought that I have turned it off, but it seems like I didn't! Thanks again!

Glad to help. Safe Surfing.