Question regarding "Slide window" in sawfish

["James Hamilton" <JAMESH davistl com>]

I have bound some keys to "pack window up", "pack window down", 
"pack window left", and "pack window right".  The idea was, if I open 
a term, and then maximize it vertically, pack it left to the border of the 
current viewport, and then open another term, maximize it vertically, 
and pack it right, I will be able to see a lot of text on both terms at once.
However, I sometimes have to hit pack window left or right several 
times to actually get the window to the edge of the screen, even if
there are no windows on the current viewport.  Does anyone know why 
this happens?  Any solutions?  I am using Nautilus to draw my desktop, 
if that is relevant.

James