XPS 13 Developer Edition and KM717; some key modifier combinations not working

Hi all,

I have the KM717 wireless keyboard (and WM527 mouse, if it's relevant), and some CTRL-... combinations don't work. They work fine on the laptop's keyboard and also a KB216t wired keyboard. Combinations that don't work include:

• CTRL-Tab
• CTRL-right-arrow (left, up and down) works
• CTRL-Z through CTRL-N (most of the bottom row)
• CTRL-home, CTRL-end, CTRL-pgdn (pgup works)
• CTRL-F1 and CTRL-F12 (the other F keys work)

Additionally, the Fn button doesn't give me access to Print Screen Scroll Lock or Pause Break.

I'm using the English (US) keyboard layout, and am using Ubuntu's "Keyboard Layout" app to test these key combinations. Ubuntu version 19.04 (disco).

Any thoughts on how to debug and resolve this?

Thanks!