Rated 2 out of 5 stars
"This extension breaks Greasemonkey's UserScript Tab in Firefox Add-ons Manager.
For anyone else having this problem, the culprit is a once useful add-on, MR Tech Toolkit 6.0.4. It makes some changes to the Add-on Manager which seems to block Greasemonkey. I've tried disabling everything relevant to the Add-on Manager in the settings, but the only solution is to disable or uninstall MR Tech Toolkit.
Incidentally, MR Tech Toolkit also stops the Add-on Manager appearing in a tab which is pretty sad since that was a feature it offered."
Same problem here.