Thunderbird does not obey Font setup
 

In The latest Thunderbird (1.0.6), I've set up all to plain-text (accounts menus) and fonts to MIscFixed 16px (minimum 16px too) in the Preferences > Fonts menu.
All Text is being displayed in my desired 16px fixed-width font, except the text you type in the composing window, when writing new mails.
There the font is ultra small, hardly even readable.
Can anyone tell me, where to set up the font for the composing window in Thunderbird (for plain-text messages)?

Thanks in advance,
--polemon

OK, i solved it:

The Composition window starts as Encoding 'Western' therefore there the correct setup needs to be (even wehn default encoding is set to UTF-8, like mine)