With two X applications open, closing one does not give focus to the other

[jamii]

If I open two X applications, place the cursor over the second and close the second, the first doesn't receive focus.

If either application is a wayland application, or if the cursor is on the first when the second is closed, the first gets focus as expected.

jamie@machine:~$ lsmod | grep nvidia | wc -l
0
jamie@machine:~$ swaymsg -t get_version
sway version 1.4

sway.log - https://paste.sr.ht/%7Ejamii/61fea9d2ab7465c6431de4e7bfd91ff4858f6247

Reproduced with this config - https://paste.sr.ht/%7Ejamii/0ff6f3916457f0b3cc2b04c98f465ce35e36c0d8

Possibly relevant - each time I trigger it I get something like this:

2020-04-16 15:21:09 - [xwayland/xwm.c:1274] xcb error: op ChangeProperty (no minor), code Window (no extension), sequence 326, value 4194407
2020-04-16 15:21:09 - [xwayland/xwm.c:1274] xcb error: op ChangeProperty (no minor), code Window (no extension), sequence 327, value 4194407
...
2020-04-16 15:30:03 - [sway/input/cursor.c:730] denying request to set cursor from unfocused client

[Xyene]

Hi, are you able to reproduce this with the latest sway/wlroots master? I just tried reproducing this with xterm, and wasn't able to.

[jamii]

Huh, I can reproduce this on sway master but not with xterm.

The original behavior was observed with both emacsclient and firefox. After setting MOZ_ENABLE_WAYLAND=1 firefox behaves correctly, so I assumed it was a general X problem. But I should have included that detail, sorry.

Experimenting some more - if I open multiple emacs processes then they behave fine. But if I open multiple windows from one process (eg via make-frame) or if I use emacsclient I can reproduce this. Similarly starting multiple firefox windows with firefox --new-instance is fine, but making a new window with Ctrl-N is not.

With multiple windows, only every other window gets focus:

I'm trying to think of simpler X programs with multiple windows that I could test this with.

[Xyene]

Of course the simplest reproduction doesn't work :)

I've been able to reproduce this with Chromium, latest sway/wlroots master (99897a6) and Xwayland 1.20.8. A simpler reproduction would be useful for tracking this down, though.

[jamii]

I'm unable to repro with this simple SDL program https://git.sr.ht/~jamii/sway-focus-issue/tree/master/main.c.

On my machine it reports info.subsystem == SDL_SYSWM_UNKNOWN. I see a lot of [xwayland/xwm.c:830] XCB_CREATE_NOTIFY (6291458) [sway/desktop/xwayland.c:611] New xwayland surface title='(null)' class='(null)' in the sway logs and if I set SDL_VIDEODRIVER=wayland it reports info.subsystem == SDL_SYSWM_WAYLAND, so I think UNKNOWN means I'm doing it right and getting xwayland.