I recently updated my version of Firefox at work to find that some helpful developer had created a version (be it slightly limited) of the inspect element tool from Firebug within Firefox. This is OK I thought, maybe I can get rid of Firebug and use this. Ummm, no. After about 10 minutes I found it was no where near as useful, and continued to use the Firebug option in the menu when I right clicked on the page.
The issue I found a few days later is that I kept clicking on the wrong menu item within the menu to inspect element. After about the 20th time of doing this I decided there must be a way to disable it and I went looking under the hood in the about:config page. Sure enough there is an option to turn off this feature called devtools.inspector.enabled, which is set to true by default. Changing this setting to false get’s rid of the menu item, and to be honest is the only way to go when you have Firebug installed.