With wayland, only xwayland windows are shown in the capture dropdown

[dolfandringa]

When running under wayland, the capture dropdown only shows xwayland windows. Even though pipewire allows me to share a specific window, and only that window is shown in the browser, the capture bit doesn't allow me to select that window, meaning I can't capture the stylus with coordinates relative to that window. In combination with #229 that makes it impossible to use weylus with non xorg programs in a dual monitor setup. Since pipewire support works just fine by itself, showing the right windows in the capture dropdown would be a really good solution for me that also mitigates issue #229.