UI freeze and CPU spikes when switching keyboard layouts

October 29, 2026 13:48 Updated

Problem

Switching keyboard layouts (e.g., between English and Ukrainian) in RubyMine causes severe CPU spikes (120-150%) and temporary UI freezes (2-5 seconds).

Cause

This issue may relate to the interaction between IDE's underlying Java environment and the keyboard input method.

Resolution

Modify the <ide>.vmoptions file (or navigate to Help | Edit Custom VM Options) by adding the following configurations:
```
-Djava.awt.im.disable=true
-Dsun.java2d.opengl=true
-Dsun.java2d.xrender=false
-XX:+UseG1GC
-XX:+UseStringDeduplication
-XX:SoftRefLRUPolicyMSPerMB=50
-XX:ReservedCodeCacheSize=512m
```
This addresses the issue by disabling problematic input method handling and optimizing graphics settings.
Migrate from ibus to fcitx5 input method framework. This change eliminates the input method issue that contributes to the UI freezes and CPU spikes.