Turn Windows Aero themes on. Right click the Desktop, select Personalization.
Now if I could just isolate the setting in the Aero Themes that causes the problem. I prefer having all of the fancy stuff turned off to improve performance.
Jim S. nailed it. I had the exact same problem even bought a whole new video card thinking that was that was the problem. The video card was not the problem, it was that I too did not want all the fancy windows theme graphics running in the background, thinking this would help speed performance. This was explained to me: with Aero off Windows deactivates the high end video graphics our video cards are there to provide. This in turn causes SW to have the exact problem you have. Have to have those features on and Aero does it.
This forum taught me this a few months ago, there are a few threads on it here. Just turn on Aero and it all starts working like it should.
Here's an example image: http://imgur.com/ZYMqZ
Here's an example image with the issue boxed in red: http://imgur.com/NJxPf
This is repeatable by clicking on an a part, holding control, and then attempt to zoom away with the mouse. It also occurs randomly when not holding control. To exit the mini-window you have to click on a part in the mini-window or on something in the tree or hit space. It makes selecting multiple parts pretty frustrating.
How do I fix it or has anyone seen this?