This is how Natron looks in Plasma, also Gimp and G’mic, but they all are fine in Gnome.
How can I fix It?
Operating System: EndeavourOS
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Kernel Version: 5.15.13-arch1-1 (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 3070/PCIe/SSE2