Tested this on Trunk 18-Feb and it still doesn't work. Bookmark created is empty , so the link to https://bugzilla.mozilla.org/sidebar.cgi is never added nor the flag that it should be loaded in the sidebar.
This was fallout from my patch in bug 277490. It was fixed by the followup patch (bug 277490 comment 11).
The Feb 19 build should have the fix.
sorry for bugspam, long-overdue mass reassign of ancient QA contact bugs, filter on "beltznerLovesGoats" to get rid of this mass change