Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

If there is still a problem,

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

While you are in Troubleshoot(Safe) mode;

Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

How to disable Hardware Acceleration {web link}

Just got the latest firefox update, now i can't play zynga poker. https://apps.facebook.com/texas_holdem/ before update, i can play it, but after 1 day it slows down, have to close and restart firefox. it happened also in Developer edition. It never happened on chrome.

After update the latest:

An error occurred running the Unity content on this page. See your browser JavaScript console for more info. The error was: SecurityError: Navigator.getGamepads: Document's Permission Policy does not allow calling getGamepads() from this context.

Many site issues can be caused by corrupt cookies or cache. Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

If there is still a problem, Start Firefox using Troubleshoot(Safe) Mode {web link} A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there? While you are in Troubleshoot(Safe) mode; Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches. How to disable Hardware Acceleration {web link}

i did that, didn't help me.

uninstall and reinstall solved the problem

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems.