Hi @Litjan, @Cameron,
Thanks for your help. With your assistance I've managed to fix the problem. It seemed like the Avitab-Browser plugin was wedged in between the Avitab and the text drawing. Here's an illustration on what happened. I'm simply drawing a full red screen (see attachment). The AviTab background is hidden (red is on top), but their text is drawn on top of the red square.
I have managed to mitigate the problem though by cleverly managing some AviTab datarefs. See the second attachment.
Thanks again for your help.