A DESCRIPTION OF THE PROBLEM :
According to https://github.com/openjdk/jdk/blob/285ceb9ee51e064687da6fc3fbed984e34cf02e6/src/java.desktop/unix/classes/sun/awt/X11/XWindowPeer.java#L766, it appears like KWin is assumed to always send synthetic ConfigureNotify events. However, the internal KWin implementation details have/will be changed in 6.2 to match the behavior described in ICCCM 4.1.5, i.e. if the client window is resized, no synthetic configure notify event will be sent. The reason for that was to fix some issues during interactive resize.

Unfortunately, it breaks pointer input under certain circumstances.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Have a machine running KWin 6.2, it can be either built from source code (https://develop.kde.org/docs/getting-started/building/kdesrc-build-compile/) or one can download the KDE Neon Testing or Developer edition.

- download JDownloader2 app, and open it
- right click anywhere in the download list, dismiss the popup
- maximize the JDownloader2 window
- right click again, and hover entries in the popup window
- the context menu entries are not highlighted as expected and pointer events have an offset

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
pointer input has some offset after maximizing JDownloader2 window
ACTUAL -
no issues with pointer input

CUSTOMER SUBMITTED WORKAROUND :
If KWin is forced to pretend to be Mutter by changing the WMName property, then the issue cannot be reproduced. The issue is reproducible both in Plasma X11 and Plasma Wayland sessions.

FREQUENCY : always