When enumeration was impossible the tool answered "could not determine the
window underneath (the desktop app did not answer, or window enumeration is
unavailable on this system)" — true, and a dead end. On Linux the two ways it
fails have opposite fixes and neither is guessable from that: a Wayland session
withholds window identity from applications outright, while an X11 session
needs xprop and xwininfo installed, because that is what the enumerator shells
out to.
Answer with the reason instead of nothing. A session with both WAYLAND_DISPLAY
and DISPLAY is XWayland, where xprop can still answer, so it gets the tooling
advice rather than being told to change session type.
