anything needed to get thunderbird links to open in minefield?

[sean darcy]

rawhide, updated. thunderbird-3.0-1.beta2.fc11.i586
firefox-3.1-0.7.beta2.fc11.i586

Clicking on a link in t'bird no longer opens a firefox/minefield tab.
Is there some new preference I'm missing? System->Preferences->
Preferred Apps has firefox.

I don't see a bug report, so wonder if I'm missing something obvious.

sean