Links in T-Bird don't switch to Firefox

[Paul Lemmons]

It used to be (karmic) that when I clicked on a link in T-Bird it would 
rotate my screen to the desktop containing Firefox, open the page and 
display it. Now (lucid) it will send the request to Firefox and it will 
open the page but focus does not follow the request. I have to click to 
Firefox manually. Does anyone know if there any way to restore the 
previous (preferred) behavior?