Thunderbird and launching Firefox browser

[Basil Chupin]

Using Lucid, and Thunderbird 3.0.4 with Firefox 3.6.3 on a 32-bit system.

On another distro I can click on a link mentioned in an email and this 
automatically starts Firefox if it is offline or opens a new tab if FF 
is already running.

With Lucid I cannot do this.

I do have Launchy installed - but I do not think that this is where the 
problem lies.

I also have TB and FF as the default applications in the System Preferences.

What is puzzling me is that I can go to System>Preferences>Appearance 
and click on the links Get More Backgrounds or Themes and in both cases 
Firefox is automatically started (or the correct web page brought up). 
But this does not happen from within Thunderbird.

Does anyone know what is needed to be done to get a URL link in TB 
activate FF? For example, in an email someone supplies a link to a 
YouTube video; I used to click on that link and the video would be 
automatically brought up in Firefox. How to get this feature back in 
Ubuntu, anyone?

BC

-- 
In a period of great joy and pleasure you are comforted by the thought that tragedy is just around the corner.