Idea incredibly laggy on Linux

From About window in the IDE:

```

IntelliJ IDEA 2025.3.3
Build #IU-253.31033.145, built on February 20, 2026
Source revision: 212d61deaf3a8
Runtime version: 21.0.10+7-b1163.110 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Toolkit: sun.awt.X11.XToolkit
Linux 6.17.0-19-generic
Ubuntu 25.10; glibc: 2.42
GC: G1 Young Generation, G1 Concurrent GC, G1 Old Generation
Memory: 4096M
Cores: 16
Registry:
 ide.experimental.ui=true
Non-Bundled Plugins:
 com.intellij.plugins.vscodekeymap (253.28294.218)
Kotlin: 253.31033.145-IJ
Current Desktop: KDE

```

My system:

Operating System: Kubuntu 25.10
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.17.0
Qt Version: 6.9.2
Kernel Version: 6.17.0-19-generic (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: NVIDIA GeForce RTX 4090
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7D52
System Version: 1.0

Just tried a 2022 version oh my good it's so smooth

by the greatness of bineary searching I found a perfection version of this software.

2022.3 ok 
2025.1 bad - scrolling is okay, but if I select something it lags like crazy
2024.3 bad - same as 2025.1
2024.2 bad - same as 2025.1
2023.2 okaish - select and drag kind of laggy, but it's on par with older ui. other stuff seems okay
2023.1 okaish - same as 2023.2

and so:
2022.3 WINNER, with the older ui. despite a few newer versions being okay-ish, they implemented a new ui which surely is full of bugs and I can't use an even newer version since they perform like ass.

Please try switching to native Wayland support mode 

In 2025.3:

Add `-Dawt.toolkit.name=WLToolkit` to “Help | Edit custom VM options” and restart 

In 2026.1

This is the default mode

It's just as bad (with classic theme disabled). With classic theme enabled, it's slightly worse.

Just in case, how to disable the “native Wayland support mode” in newer versions?

Okay I tried the 2026.1 version and it did improve by about 40%. Feels like it's running on 40-50 fps.

Now, compared the the classic ui on the 2025 version without the native support, it still miles off. I get my full 144fps of UI updating, which is smooooooth as butter.