I have encountered a very strange behavior in Windows 7 that I cannot seem to identify and I have never seen or heard of on any system configuration. Whenever I move my mouse to the left-most edge of my primary display (centered in 3-display setup), my desktop icons magically move away from the cursor (up or down and to the right). It only happens when my desktop has focus and the mouse is positioned on the left, top or bottom edge of the main display. Moving the mouse all the way to the right edge of my right secondary display causes the mouse icons to snap back into their correct position.
My setup is 3 displays on two display adapters. The main display is running at 2560x1600, connected to the machine via a USB-powered DVI-D to DisplayPort adapter and is driven by an NVIDIA NVS 3100M video card. The secondary displays are running at 1440x900 and 1200x1920 and are driven by integrated Intel HD Graphics (mobile).
It seems like some kind of panning behavior, but it's obviously not working as expected. I have updated all of my drivers, but no change. It's probably worth noting that the desktop icons are set to auto-arrange.