在VMWare中使用Windows 7上的双显示器时，无法更改主显示屏

I am running Windows 7 RC Build 7100 in VMWare 6.5. The host OS is Vista x64 Home Premium running on a Dell Studio 1535 laptop. I have a Dell monitor attached as a secondary monitor, and I am attempting to share the desktop across both monitors. I am running Windows 7 RC Build 7100 in VMWare