Filter Drivers stop working when USB port changed.

It seems that when a device using a filter driver is moved to a different USB
port, it stops working. The filter driver no longer works and needs to be
re-installed. In XP, when a device is moved to a different USB port, all
drivers stay intact.
In Vista the PC will do a new search for drivers for the device and
re-install them when found, but will not re-install the filter driver and
will give no prompt about this. The functionality provided by the filter will
simply not work unless the user manually re-runs the device installer which
re-installs the filter.