Ever come across a site that won’t allow you to right-click? Some sites block the ability to right-click usually via JavaScript so you can’t say copy or download images. However, it is rather frustrating on a site such as a message board where Firefox underlines a misspelled word, but you can’t right-click to correct or ignore. A very quick about:config settings change will “fix” this for you:

1. In a new tab type in the address bar about:config and press enter
2. If you get a warning about “Voiding your Warranty” click the I’ll be careful, I promise button to continue
3. In the Search box type context
4. In the list of preferneces that show below located and dobuble-click dom.event.contextmenu.enabled to change the value to false
5. Close the about:config tab
6. Return to the site/page that was preventing you from right-clicking and try now. Note: You may still get a warning about right-clicking not allowed, but the context menu should appear now.

via wikiHow