You might want to experiment with using this program to run DW,
DXWnd. On the input tab there are some more mouse tweaks. Maybe it can solve your problems. No guarantees though. I have not tried it (these mouse settings) and don't have the same problems as you.
Guide to fix pallete/window issues by FPS Chazly using DXWnd:
http://www.subsim.com/radioroom/show....php?p=2543791