Editing pages in the Index namespace for the ProofreadPage extension doesn't work with the enhanced toolbar in Firefox 3.6, Opera 10.10 and Chrome 4.1.249.1059.
It works in the above browsers with Vector enabled and with the enhanced toolbar disabled.
There's no problem in Windows Internet Explorer 8.
I tested it in en.wikisource and in he.wikisource.
I should add that the enhanced toolbar is quite useful in Wikisource for adding special characters in Latin and in Hebrew.
Version: unspecified
Severity: critical
OS: Windows XP