Theme `<colorOverride>`s are not honoured

[jamiebird-arm]

Let's make sure issue is not already fixed in latest builds first.

• I verified I can reproduce this issue against latest Integration Build of Eclipse SDK

Summary

Theme <colorOverride>s are not honoured.

It seems that theme <colorOverride>s are not honoured. This can be reproduced using the built-in "Reduced Palette" Color and Fonts theme.

Steps to reproduce

Using the ERROR_COLOR <colorDefinion> as an example, the base theme defines it as COLOR_RED:
https://github.com/eclipse-platform/eclipse.platform.ui/blob/master/bundles/org.eclipse.ui/plugin.xml#L1611

      <colorDefinition
            label="%Color.errorText"
            value="COLOR_RED"
            categoryId="org.eclipse.ui.workbenchMisc"
            id="ERROR_COLOR">
         <description>
            %Color.errorTextDesc
         </description>
      </colorDefinition>

And the Reduced Palette theme has an override as COLOR_LIST_FOREGROUND:
https://github.com/eclipse-platform/eclipse.platform.ui/blob/master/bundles/org.eclipse.ui/plugin.xml#L1925

         <colorOverride
               id="ERROR_COLOR"
               value="COLOR_LIST_FOREGROUND"/>

When the Reduced Palette theme is active, the preference still appears as red:

Default theme:

Reduced palette theme:

Secondly, when non-default themes are active, hitting 'Reset' defaults to BLACK. Hitting 'Reset Defaults' sets BLACK for most color preferences and make the IDE relatively unusable.

This seems like a regression of #2421. At least since 2023-12 (4.30.0).

Tested under this environment:

• OS & version: Ubuntu 22.04 & MacOS 15.5
• Eclipse IDE/Platform version (as shown in Help > About): 2025-12 (4.38.0) & 2023-12 (4.30.0) - though the second part is not an issue in 2023-12.

Community

• I understand reporting an issue to this OSS project does not mandate anyone to fix it. Other contributors may consider the issue, or not, at their own convenience. The most efficient way to get it fixed is that I fix it myself and contribute it back as a good quality patch to the project.