The mini-view isn't fully supported - it should work, but you have to adapt the full size layout.
Make sure you have at least version
1.19.6, and that you enable the 'use new prima software' option on the Layout Manager "Options" menu. (I guess you're already using this?)
There is a known issue with flickering at Prima in Vista, and there is no fix for this yet, I'm afraid. There is some incompatability somewhere between Vista, Prima and PAH.