Fonts in mozilla menus

[Joerg Johannes <liste_joerg@gmx.de>]

Hi list

I have just started to try mozilla for e-mailing. The problem I have is: 
How do I change the font that is used in the menu bar and the message 
index? These are way too big (see screenshot at 
http://btcpxx.che.uni-bayreuth.de/CIP/biochem/bp0026/www/mozilla-font.png 
for better understanding.
If I change the font size in the Preferences>Appearance>Fonts menu, only 
the font size of the message body changes, but the size there is OK.

Thanks
joerg