Remote execution flaw mars older Thunderbird versions
http://www.theregister.co.uk/2009/12/11/thunderbird_threat/
Using TB 3 without any problems at all
Now that leaves me with a dilemma. Continue with TB2 until they update Lightning to work with TB3, or sacrifice Lightning for the time being and upgrade. (My theme is incompatible too - but I found the same with FF 3.6 and have managed to live with what I can get).
Steve