No screen refresh in Abiword 2.6.8 edit view after scrolling with mouse wheel

ros 0.4.5RC1 (branched around trunk r74422)
after installing Abiword 2.6.8
you can usually edit the text in the default edit document (although we see no blinking cursor.)

However after scrolling with the mouse wheel there is absolutely no drawing refresh in the main view (you don't see what you type).

After minimizing and restoring the Window, the draw-refresh is working again until you scroll the next time.

Nothing gets logged when this happens.