Kensington orbit scroll ring trackball not working

[Rich Shepard]

Running xfce4-4.12 on Slackware-14.2. For many years I used Logitech
trackballs and the latest finally died of old age. To replace it I bought a
Kensington orbit trackball with scroll ring and it arrived yesterday
evening.

When connected to my older desktop via a USB->PS/2 connector, the trackball
did not work; that is, the cursor would not move. Connected directly to a
USB port in the front allowed it to work.

Settings -> Mouse and Trackball defaults to "ImExPS/2 Logitech Explorer
Mouse" (which worked with the old Logitech trackball and any actual mouse I
plug in a USB port). The other alternative is "HID 04d9:0499". When the
Kensington trackball is plugged in a third alternative reads "Primax
Kensington Eagle Trackball".

With the mouse disconnected I tried making the Kensington Eagle Trackball
the driver. It appeared to not stick for a few tries, then it apparently did
because with only the Kensington trackball connected the settings dialog box
blanked and cursor would not move in the PS/2 port; had to connect a mouse
to recover. Now (even after restarting X) the trackball will not move the
cursor even when connected directly to a USB port. Very strange. And,
resetting the device to defaults makes no difference: the Kensington
trackball now refuses to move the cursor connected via the USB->PS/2 adapter
or directly to a USB port.

I need advice on what to do to enable the Kensington trackball to work
connected through an adapter to the PS/2 port on the rear of the host.

Regards,

Rich