Add EWMH support for XWayland windows (_NET_CLIENT_LIST, _NET_ACTIVE_WINDOW)

[Marcus-Arcadius]

Description

cua-driver (and other X11 automation tools) cannot discover or match XWayland windows on ShojiWM because the XWayland root window is missing EWMH properties:

• _NET_CLIENT_LIST — not found (no window list)
• _NET_ACTIVE_WINDOW — returns 0x0 (no active window tracked)
• _NET_SUPPORTED — only lists a few atoms, not the full EWMH set

Impact

Tools like cua-driver, xdotool, wmctrl, and other X11 automation utilities cannot:

• Enumerate visible windows by name/class
• Match app names to window IDs
• Focus or activate specific windows

Environment

• ShojiWM (latest from flake)
• NixOS 24.05+ (unstable nixpkgs)
• xwayland-satellite enabled
• cua-driver 0.7.1 (reports "6 visible top-level windows" via X11 but cannot match any app names)

Proposal

Implement EWMH compliance for the XWayland root window:

1. Maintain _NET_CLIENT_LIST with all XWayland toplevel window IDs
2. Track _NET_ACTIVE_WINDOW based on the focused Wayland toplevel
3. Advertise supported EWMH atoms in _NET_SUPPORTED
4. Set _NET_WM_NAME and WM_CLASS on XWayland windows (may already work via xwayland-satellite)

This would enable X11 automation tools to interoperate with ShojiWM-managed windows.

[bea4dev]

Thanks for the report.
This is probably an issue with xwayland-satellite, but I’ll look into it on my side as well.
I suspect that fixing this may require some help from the compositor side, and that it might not be possible to fix in xwayland-satellite alone. If necessary, I’ll consider adding support for it.