Apparently Firefox 1.5 may not play nicely with Greasemonkey, whether the whole thing or the individual scripts. Let's see how this impacts tagging for categories, whether this requires some script reconstruction, & whether there's a new greasemonkey version on the horizon....
Update 12/01: Johan reports that the new greasemonkey 0.6.4 is out & available, for all of you who upgraded to Firefox 1.5. See Userscripts.org for the updated version, & for the wiki that will tell you how to fix any scripts that remain broken w/ the new version.
