doMove_Classes(): use GetWindowRect() to compute upper-left of the window. Fixes 'window drift' redisplay bug.
doMove_Classes(): use GetWindowRect() to compute upper-left
of the window. Fixes 'window drift' redisplay bug.

FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs