Since the last two versions, I have an annoying bug: As soon as I zoom into a picture, I recieve an rectangular artefact in the lower right corner (fig 1). If I have been in the browser view directly before, I see tiles with thumbnails inside the artefact (fig 2). Is that an already known bug (even if I WAS searching the forum before), am I doing sth wrong (missing option, screen resolution etc?) or is anything known about hardware related causes?
fig 1:

fig 2:

Windowx XP Sp3 on LGP310 with Nvida M9500GT, XnView running on second monitor Eizo 22" 1680*1050