What happens when you click on the Content tab?

Does the issue still occur if you start Firefox in Safe Mode? http://support.mozilla.com/en-US/kb/Safe+Mode

How about with a new, empty profile? http://support.mozilla.com/en-US/kb/Basic%20Troubleshooting#w_8-make-a-new-profile

works fine in safe mode. Before clicking content tab had no effect at all. reason I wanted to was because a page was telling me javascript was disabled and I was trying top activate it.

If it works in Safe Mode, chances are an extension is interfering. Try http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes