SUMMARY
KWin Wayland locks up when entering or leaving breakout groups in Zoom (the comms app from https://zoom.us). The mouse pointer freezes and no keyboard input is accepted. The only way out is REISUB or a hard reboot.

This happens regardless of whether Zoom is started in regular Wayland, in XWayland (`QT_QPA_PLATFORM=xcb zoom`), or in a separate kwin_wayland session (`export `dbus_launch `, `kwin_wayland --socket test`, `WAYLAND_DISPLAY=test zoom`)

Tested with KWin 5.24.4 and the factory RPMs for Zoom 5.10.4 (2845) 64bit on OpenSUSE Tumbleweed.

STEPS TO REPRODUCE
1. Open Zoom, join a Zoom conference
2. In the conference, enter or leave breakout groups.

OBSERVED RESULT
Zoom opens a floating popup window that tells you you're joining the breakout group or rejoining the main session. At this moment KWin locks up.

This might be a DBus issue; however, even after waiting for 10 minutes the session does not unfreeze again.

EXPECTED RESULT
Whatever bugs Zoom may have (see below for other Wayland issues), KWin should not freeze.

SOFTWARE/OS VERSIONS
Zoom Version: 5.10.4 (2845)
Operating System: openSUSE Tumbleweed 20220415
KDE Plasma Version: 5.24.4
KDE Frameworks Version: 5.93.0
Qt Version: 5.15.2
Kernel Version: 5.17.2-1-default (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620

ADDITIONAL INFORMATION
Zoom is a Qt application.
Zoom has other window management issues on Wayland as well; e.g. when starting Zoom in regular Wayland (i.e. not in XWayland) the Zoom process quits often upon entering a conference. If this happens in a nested Wayland session, an "Error in client communication" message is generated, with the Zoom PID. While this is probably a Zoom bug, these bugs should not lead KWin to lock up.