Problem with scrolling split window using trackpoint

[dannyyuan]

Hi,

I split my emacs frame into two windows, and tried to scroll the
buttom window using middle button. That is, I held down the middle
button and push the trackpoint (it should be similar to holding down
the middle button on a mouse and moving the mouse, but I'm not totally
sure). However, no matter where the mouse cursor is focused, it was
always the upper windows that scrolled. My system: Windows XP SP2 on
T42P. Emacs version: EmacsW32 with This is GNU Emacs 22.0.92.1 (i386-
mingw-nt5.1.2600).

Any suggestions? Thanks!