Windows Vista Desktop icons scrambled when undocking

Running Vista SP2, 32bit. When I undock my laptop, the icons on my desktop are re-arranged. I know it's due to the difference in screen size & resolution between the laptop screen and the monitor on the dock. I was wondering if there is a file that I could save before undocking that I could use to restore the icons to their previous locations when I re-dock. Manually restoring them is tedious and time consuming.