Only Talkback in TB, several in FF.
Talkback 1.5.0.10 is in Thunderbird. I just added Leak Monitor 0.3.6 to both, but I don't imagine it's going to tell me much of anything.
In addition to Leak Monitor, FF 2.0.0.2 has:
Adblock Plus 0.7.2.4
Fasterfox 2.0.0
Flashblock 1.5.2
Tab Mix Plus 0.3.5.2
Table2Clipboard 0.0.2.1
Spellbound and Talkback 2.0.0.2 are disabled. I had trouble with Spellbound [link|http://z.iwethey.org/forums/render/content/show?contentid=262912|before] and the version I was using apparently isn't necessary for the 2.x branch of Firefox.
I'm using the default themes in both.
In Thunderbird, I can see a general trend in increasing memory usage after each check of my POP account, but it's not a constant increase.
I wouldn't be surprised if the FF extensions cause problems, but I'll bet there's a fundamental leak in the base code.
Cheers,
Scott.