Created attachment 157932 [details]
Screen recording

SUMMARY

When entering some code in the IDE, the code completion window pops up. However, while typing this window flashes at random positions with random scaling and size and sometimes appears just as a black rectangle for fraction of a second.

Even worse, it can make the compositor completely freeze for a minute or so, where even keyboard or mouse input stops working. You can notice that the compositor first slows down while typing as there's a certain input lag until it becomes fully unresponsive.

Journalctl had logged the following (1085 times, i.e. 22 events per second):
> 19:19:22 kwin_wayland_wrapper[2179]: Key repeat discarded, Wayland compositor doesn't seem to be processing events fast enough!
as well as
> 19:19:22 kwin_wayland[2127]: kwin_core: XCB error: 3 (BadWindow), sequence: 52994, resource id: 18926880, major code: 129 (SHAPE), minor code: 3 (Combine)

When it finally had cooled down again, instead of an `else` I had `elllllllllllllllll(....)llllll` with roughly 1400 `l`s in the code input area. 

This seems to be a regression as I definitely could not observe these issues in 5.26 or prior. 


STEPS TO REPRODUCE
1) Dual screen: 2k@100% on the left, 4k@200% on the right + primary
I could not observe it with any other constellations so far. Unfortunately this is the setup I currently got to work with.
2) Please see the attached screen recording.  


SOFTWARE/OS VERSIONS
Operating System: openSUSE Tumbleweed 20230404
KDE Plasma Version: 5.27.3
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8
Kernel Version: 6.2.9-1-default (64-bit)
Graphics Platform: Wayland
Processors: 24 × AMD Ryzen 9 5900X 12-Core Processor
Memory: 31.2 GiB of RAM
Graphics Processor: AMD Radeon RX 580 Series

PyCharm 2023.1 (Professional Edition)
Build #PY-231.8109.197, built on March 29, 2023
Runtime version: 17.0.6+10-b829.5 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.