output history help

[sims@starbase.MITRE.ORG (Jim Sims)]

 I have an application that uses a map *much* larger than the screen, that I
want to draw lines on. I wrote a function to do rubber-banding lines using
dw:tracking-mouse, drawing and XORing the lines to get the rubber-band effect.
Whenever I scroll the lines off-screen and scroll back to them, *ALL* the 
rubber-banded segments get redrawn (UGLYYYY!!) as weel as the final (intended)
line segments.
 I tried wrapping a (dw:with-output-recording-disabled ()) around the:
   function call
   portions of the functions doing the graphics:draw-line
   both of above,
to no avail....
Help anyone?
Thanks in advance,
jim                         (sims@starbase.mitre.org)