Unable to change IDE theme

What is the version of IntelliJ IDEA and OS in use? 

Typically, the select box is grayed out in case "Sync with OS" checkbox is set: 

I'm running IntelliJ on Manjaro Linux, and the IntelliJ version is 2021.3.2 (Installed with toolbox).

I don't know why I don't have "Sync with OS" option in my Appearance menu

It is not yet implemented on Linux. 

Do you sync your settings with an IDE on Windows? 

Could be related to https://youtrack.jetbrains.com/issue/IDEA-283945

That's it! You are totally right, I removed the sync and now I'm able to change theme again.

Thanks!

I have the same problem with `2023.1` on Ubuntu.

I do not sync with Windows but during the first start I selected sync with OS (which is dark) and now I can't change the IDE theme, it is stuck to DarK

Please attach information from "Help | About" (click on "Copy" and paste data here)

You can delete "~/.config/JetBrains/IntelliJIdea<version>" to reconfigure IDEA. Similar actions may be useful for other JetBrains products as well.

You can be less distructive simply changing the autodetect attribute of component node to false in the file ~/.config/JetBrains/{ide-version}/options/laf.xml, something like:

<application>
  <component name="LafManager" autodetect="false">
    <laf class-name="com.intellij.ide.ui.laf.IntelliJLaf" themeId="JetBrainsLightTheme" />
    <preferred-light-laf class-name="com.intellij.ide.ui.laf.IntelliJLaf" themeId="ExperimentalLight" />
    <preferred-dark-laf class-name="com.intellij.ide.ui.laf.darcula.DarculaLaf" themeId="f92a0fa7-1a98-47cd-b5cb-78ff67e6f4f3" />
  </component>
</application>

Thanks Marco Sacchi it worked nice for me ! Some feature here may need to be adjusted.

Same issue after uninstalling the plugin "Auto Darkmode", the fix of Marco Sacchi worked flawlessly, thanks !