Thunderbird 12.0 does not open when I use "send link" in Firefox 12.0. Thunderbird is working and running. The usual new mail window does not appear.
In Firefox: Edit → Preferences → Applications → mailto is set to "Use Thunderbird Mail".
I tried to set this to "Always ask", when I try to send something, I can select "Thunderbird", but nothing happens, when I press "OK".
(Also, in about:config "network.protocol-handler.external.mailto" is set to "true".)
By the way, I use Gnome instead of Unity. Can this be the reason for this behaviour?