It seems that Gmail released a little change just for Firefox 3.6+ that stops us rendering buttons correctly, so you will see ‘Search in Popup’ and ‘Send and’ as plain text.
In 22.214.171.124 I’ve fixed this. I also fixed a problem where GTDInbox could no longer detect adding/removing status labels to update the count of ToDo items (so the #todos would become inaccurate as you used Gmail).
As per usual, you can grab it right now from http://www.gtdinbox.com/gettingstarted.htm.
This was written by Andy Mitchell