Another fun question about Vista. This happens on both my office PC at work with its mouse, and my home laptop which does not use a mouse. Sometimes, when I pull the cursor across the screen where there are two or more windows open (with one partly hidden by the top/active window), the context will switch to the window that was underneath, as the mouse cursor passes over it. This happens even though I do not click any mouse buttons. It's darned annoying, and not reproducible so far as I can tell. My search of the web did find a mouse-hover-switch-windows "feature", but I checked my mouse control panel settings, and that is not enabled. Thanks for any thoughts or things to check.