[TxMt] How to delete the 'BG' color in a theme's pref-list

[Dave Lenz]

Hi there...

Maybe I'm overlooking something but I can't seem to find it...
I'm in the 'Fonts & Colors' prefpane of TextMate and I want to delete  
some BG-colors of some elements. Each time I click on an element's BG  
I get a color-popup asking me to pick a color. What if I don't want a  
color... It's still gives me a color-square under the BG-column. How  
do I delete the BG?

Greetings
Ypmits