Hi krass, that's just a normal type of display artifact that can happen because the display is overall more oriented around doing things quickly rather than having a perfect graphic result. There isn't really anything to fix for it, it's just something to ignore.

In the future I have some ideas for improving it. It probably started to get more noticeable once you had a part with a thin wall thickness on it.

Check out here for some more information:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4987.2

- Michael