Black background with black text scrolling issue

Hello - I have a strange and annoying problem going on with Thunderbird Portable 3.1.7 running under Wine 1.2/Linux (openSuSE 11.3 x64). Many of my emails are being shown with a black background and black text making them unreadable. I have tried setting all the various color options for background and text but to no avail.

Now here is the weird part. If I scroll a message using the scroll bar in the window itself, the background remains black and the text remains black. But if I scroll using the touchpad on my laptop, then the background changes to white, text remains black and the email becomes readable. But the background becomes white regardless of the background color setting in Thunderbird. The only other way I have found that lets me read these emails (which works with small messages as well) is to highlight/select all the text, using the colors for highlighted sections, so as to render the email readable...

Any ideas? I have hunted through all the options of Thunderbird, and grepped throughout .wine configuration files but so far have been unable to find anything that is obviously wrong...

Thanks in advance for taking time to reply and offer advice... Marc..