Comment 39 for bug 411358

I'm yet to do a bit more research into this but I believe that Thunderbird is basically correct in what it is doing (even though it seems daft at face value)... I can also confirm that Thunderbird has been doing this for a long time and what has changed is the presentation of the gconf errors.

This issue is attributed to the Ubuntu Thunderbird package being compiled with support for GIO. If you use the binary package from mozilla then it does not should a pop up dialog.

Thunderbird chooses GIO in preference to GConf if it's available but then GIO actually uses GConf itself to do the lookup. The error handling is configured slightly differently and this results in the pop-ups.

I need to do some more tests when I have time and then I'll try to propose a fix.