I'm trying to track idle time using
arbtt on a VM running Ubuntu 18.04 (using i3 on X11). arbtt uses the XScreenSaver protocol extension to get the time since the last input event, which seems to get reset about every 40 seconds. Running
xprintidle in a loop shows the same result, even when I'm away from the system. There is no cursor movement (the cursor stays hidden if it was hidden before), and of course no keypresses either.
How do I find out what's causing the idle time to be reset? I've tried monitoring input events with
xinput test-xi2 --root (which shows no event when the idle time gets reset) and
xev -root (which doesn't seem to work at all).
The Linux system is running in VMware Workstation 12 on Windows 10,
open-vm-tools are installed and the various integration features are working. It doesn't make a difference if the VM is focused, full-screen or even minimized.