To all those people having issues:
please try start Firefox in Safe Mode.
At the top of the Firefox window, click the
Help menu and select Restart with
Add-ons Disabled.... Firefox will start up with the Firefox Safe Mode dialog. Clicking the Continue In Safe Mode button starts Firefox in its Safe Mode. While you are in Safe Mode, your extensions and themes will be disabled, and any toolbar customizations will be reverted back to their defaults. if the problems disappear than addons are the culprit and you should update or disable them.
Else, Firefox has bugs & you should switch to some other browser