Comment 3 for bug 540820

I think this bug should be moved to the Thunderbird package (not that you can get upstream to fix anything they broke from 2.x to 3.x). There are several themes and colors this new feature will mis-behave with.

A work around is to create a chome/userChrome.css file in your Thunderbird profile directory and add this code:

treechildren::-moz-tree-cell-text(folderNameCol, newMessages-true) {
font-weight: bold;
color: #000000 !important;
}

Note that color: #000000 is black,,, modify to your taste.