Severe corruption of right click taskbar menus on windowblinds 8 with windows 8.1 preview

All "right click" taskbar menus are corrupted visually on my install of windowblinds 8 with windows 8.1 preview. No matter which visual style I use. I uninstalled, re downloaded, re installed, updated nvidia drivers to 326.01. Nothing has fixed it so far. My machine is an Asus  i5 Sandy Bridge running an Nvidia gt530 card. Only the taskbar right click menus are corrupted. All other menus and borders look fine. Any ideas? I'm all out.

Thanks in advance, Mike

PS: Here's a pictu...