[inderp]

Please verify that you've gone through these steps: 

1) Load MobileSheets, tap the three dots at the top right and then Settings.
2) Tap Touch & Pedal Settings and then Pedal Actions
3) Tap the "Keys" field for Pedal 1.
4) Tap the "Clear" button on the dialog.
5) Press a button on the accessory. If a key shows up, the accesssory is communicating properly with your device and will work with MobileSheets.
6) If a key shows up, tap OK, then select the action you want that button to trigger from the dropdown below the keys field. Repeat these steps for pedal 2 (button 2 on the accessory).

Mike

That fixed it. I thought it was something obvious, just couldn't figure it out.

I had backed up the library and restored it to try another tablet. After using it for a short while, I decided to go back to the original device, the MS Surface Go. So I did another backup and restore. I suppose that's where the settings were lost.