Previously, a WinXPSP3 session running on a WinXPSP3 host computer ran perfectly fine in a dual monitor setup. No issues with vmPlayer 2.x. BEFORE updating to vmPlayer 3, the following problem cropped up. When clicking in a single monitor, you would get exactly what you expected. However, when the display was stretched across two monitors, the clicking would be to the left of the mouse cursor. The farther RIGHT you were, the farther left the click would occur. In other words, if you clicked on the system menu of a window in the upper left of a window on the left monitor, you would get the system menu. Move half a screen to your right and the click would be on an item about a quarter of the way over, rather than where you were clicking. And by going all the way to the far right of the right monitor, you could bring up a right-click menu on the far right of the LEFT monitor. I Hope I have described this properly. It's confusing, even in words.
In single monitor mode, everything works perfectly fine. If, instead of using either UltraMon or DisplayFusion, you run a single desktop across both monitors (3200x1600), there are no mousing issues. Unfortunately, having two 1600x1200 monitors, that depth of 1600 makes that hack less than useable. My graphic card won't offer anything resembling 3200x1200.
vmPlayer 3.0 did not alleviate the situation. The microsoft mouse drivers are up to date and so are the nVidia card drivers.