This is a page about »Disable Hardware Media Keys on Firefox«.

Guide starts here

Write about:config or copy and paste it into the URL field of firefox to access Advanced Preferences.

Click Accept the Risk and Continue

Search for media.hardwaremediakeys.enabled in the search preference name field.

In the second field make sure it says false instead of true.

That’s it, if it doesn’t work after these steps, you might need to close firefox and open it up again.

Note: Google Chrome is very annoying for not giving us this option.