Screenshot IE6 with error dialog open
WikiEditor does a little browser detection to automatically fall back to the classic toolbar when on some known-broken browsers like IE 6.
Unfortunately it looks like something in the behavior for the toolbar buttons doesn't get fully left alone; when clicking any of the buttons (bold, nowiki, etc) in this mode I get a JS error:
'$iframe' is null or not an object
Disabling the WikiEditor extension, this doesn't happen.
Tested on prototype r82004 and trunk r82002