This is WIN2000 SP4 on a IBM Thinkpad A31.
The scroll wheel doesn't work for IntelliMouse PS/2 when it is plugged
into the port replicator (no PS/2 port on laptop). Mouse, right and
left buttons work fine.
The scroll wheel on a MS Optical USB mouse works fine in either the
laptop or port replicator USB port.
I installed the recommended MS IntelliMouse driver and can select and
test the buttons, but the wheel does not scroll.
I have swapped with PS/2 IntelliMouse that scrolls on another host.
Any idea on how to debug this?