To reproduce goto: https://bugzilla.redhat.com/query.cgi?format=simple Rendering this (up to a point where its responding to trying to use the form) takes 3 minutes, and thats on a dual core athlon64 with 2 gigs ram running x86_64 rawhide! I've seen long renderingtimes in other gtk apps using long listboxes too, mainly in pan the newsreader, so this could very well be an gtk issue.
No it most likely is not gtk issue. Try running firefox with GNOME_ACCESSIBILITY=0 i.e., GNOME_ACCESSIBILITY=0 firefox I think it will help and this is duplicate of bug 431162 (which has upstream in https://bugzilla.mozilla.org/show_bug.cgi?id=418845). If it isn't please reopen with additional information. *** This bug has been marked as a duplicate of 431162 ***