When I use Qt based tools, some windows are not rendering until I hovered with the mouse over the elements or they get repainted in other ways. This happens only when fractional scaling is being used.
I already opened a bug at https://bugs.kde.org/show_bug.cgi?id=514045 and there I was told by a high standing developer of that KDE is behaving correctly and I have to report it here.
STEPS TO REPRODUCE
1. Open a QT app like MakeMKV
2. Open a second window in it like the about popup under help
OBSERVED RESULT
Until the widgets get repainted the window is not visible
EXPECTED RESULT
I can see the window
SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 6.5.5
KDE Frameworks Version: 6.22.0
Qt Version: 6.10.2
Kernel Version: 6.18.7-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 5800X 8-Core Processor
Memory: 32 GiB of RAM (31.3 GiB usable)
Graphics Processor: AMD Radeon RX 7900 XTX
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: X570 AORUS MASTER
System Version: -CF