Cannot uncheck the option to "Use color scheme font instead of default"

Problem

IDE does not remember the state of the "Use color scheme font instead of default" checkbox in Settings | Editor | Color Scheme | Color Scheme Font.

It is reset after settings are reopened, and default font is not used as expected.

Cause

The issue is caused by one of the options in the IDE color settings, FONT_SCALE. It was deprecated a while ago in the course of implementing IJPL-38476, but some third-party plugins still use it. For instance, 'Material Theme UI'. If you install the plugin at least once, the option makes its way into IDE settings and corrupts them. And it is not removed when the plugin is uninstalled.

Resolution

1. Go to File | Settings | Settings Sync and press Disable Settings Sync. Check the additional box to remove the color scheme file from the cloud storage:

   

2. Close all IntelliJ IDEs

3. Remove the folder called settingsSync from each of your IDE's configuration directory - it is necessary for the fresh start

4. Check all folders called colors inside each IDE's configuration directory and determine in which IDEs the affected color scheme is installed

5. Remove the line that contains <option name="FONT_SCALE"... from all of the affected color schemes

6. Open your IDEs and enable Settings Sync back