Sys-usb blocks digitizer mouse inputs?

I installed Qubes without sys-usb.

My USB mouse and digitizer worked just fine after the install.

I then setup sys-usb for an external keyboard using:

sudo qubessctl state.sls qvm.usb-keyboard.

After rebooting sys-usb shows, and my digitizer and mouse showed in the devices applet. But the mouse aspects to the digitizer stopped working. The USB mouse works.

The digitizer identifies as a tablet. So I changed the qubes-rpc policy on qubes.InputTablet and qubes.InputMouse settings to:

sys-usb dom0 ask,user=root,default_target=dom0
$anyvm $anyvm deny

Now when I plug in the digitizer, it prompts to allow the tablet and the mouse to connect to dom0. But the mouse inputs to the digitizer still don’t work.

The USB mouse works.

I deleted the sys-usb and rebooted to test. The digitizer then works.

There is something about the sys-usb that is stopping the digitizer mouse inputs from working. Any ideas how to fix it?