Proper selection coloring in JFace Structured Viewers

[Christopher-Hermann]

Resumption of #1690

Highlighting problem when using the dark theme on Windows eclipse-platform/eclipse.platform.swt#811

JFace viewer are using OS selection color to highlight the selected item. On some OS this is not accessible. In particular when the eclipse is used with dark theme and the OS is used with light theme, this can cause really bad UI/UX experience. With this change, the selection color can be changed via color preference in the settings of eclipse.

Example
Selection color on Windows Server in dark theme looks really bad:

Testing
On start up of eclipse, the selection colors in column viewers (table and tree viewer) should look like before.
On Windows, the dark theme should predefine the selection colors to fix the bad coloring on some Windows platforms.

In the preferences (Preferences > General > Appearance > Colors and Fonts), there are 4 new properties for the coloring of the viewer selection:

• Basic > Viewer selection background (focused)
• Basic > Viewer selection background (no focus)
• Basic > Viewer selection foreground (focused)
• Basic > Viewer selection foreground (no focus)
  Changing these colors should affect the coloring of the selection in viewers. The coloring should immediately be applied as soon as the apply button is confirmed. The reset button should reset the coloring to the OS specific highlight coloring, expect for Windows dark theme, where the predefined colors should be restored.

OS Information
The fix is implemented for Windows and Mac only (no GTK).
On GTK the coloring via SWT.EaraseItem is not working properly.

Fixes:
eclipse-platform/eclipse.platform.swt#811
#1688
#1956
#2780
#3570

See:
#1690
#2793

[eclipse-platform-bot]

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

bundles/org.eclipse.ui.themes/META-INF/MANIFEST.MF

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From 5392d25fa9fcd2a878559e10634aaca219731dc3 Mon Sep 17 00:00:00 2001
From: Eclipse Platform Bot <platform-bot@eclipse.org>
Date: Mon, 12 Jan 2026 08:07:38 +0000
Subject: [PATCH] Version bump(s) for 4.39 stream


diff --git a/bundles/org.eclipse.ui.themes/META-INF/MANIFEST.MF b/bundles/org.eclipse.ui.themes/META-INF/MANIFEST.MF
index a1a0eafd86..f9d231a384 100644
--- a/bundles/org.eclipse.ui.themes/META-INF/MANIFEST.MF
+++ b/bundles/org.eclipse.ui.themes/META-INF/MANIFEST.MF
@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %Plugin.name
 Bundle-SymbolicName: org.eclipse.ui.themes;singleton:=true
-Bundle-Version: 1.2.2900.qualifier
+Bundle-Version: 1.2.3000.qualifier
 Bundle-Vendor: %Plugin.providerName
 Bundle-Localization: plugin
 Require-Bundle: org.eclipse.e4.ui.css.swt.theme
-- 
2.52.0

Further information are available in Common Build Issues - Missing version increments.

[github-actions]

Test Results

 3 018 files  ±0   3 018 suites  ±0   2h 13m 12s ⏱️ - 9m 52s
 8 229 tests ±0   7 981 ✅ ±0  248 💤 ±0  0 ❌ ±0 
23 511 runs  ±0  22 720 ✅ ±0  791 💤 ±0  0 ❌ ±0 

Results for commit c2654d1. ± Comparison against base commit 8567247.

♻️ This comment has been updated with latest results.

[laeubi]

@Christopher-Hermann please use descriptive title and PR description and also adapt the commit message. It is impossible to understand without looking at the code what is actually done here.

Beside that, its always good to show before/after screenshot for visual changes.

[Christopher-Hermann]

Added PR title & description. In the current state there are most probably some things left that needs to be cleaned up, tests are missing, etc.

But in the first place I wanted to share the coding with @fedejeanne to get the fix running on all operating systems.
In the last try there were a lot of issue especially for Linux that we need to solve...

[fedejeanne]

@Christopher-Hermann thank you for retrying this!

As agreed, I tested on Linux and I found some of the problems that were already mentioned in #1956, namely:

1. The Viewer selection foreground (no focus) does not apply in the package explorer (MANIFEST.MF) and in the Preferences (Colors and Fonts item)

This situation is worse with the default values since it's then white over white for non-focused elements (MANIFEST.MF in the package explorer)

---

2. Icons go missing, both for the focused (orange) and the non-focused (light blue) elements

[fedejeanne]

@Christopher-Hermann I now have some other odd behavior: I see half painted selections :-\

EDIT: I see the icons though, so that's good :-)

Here I changed the Viewer selection background (focused) from orange to green and Viewer selection background (no focus) to yellow and you can see that the selections still have a half-orange part, both the focused and the non-focused ones.

[Christopher-Hermann]

I tried a lot on a Linux VM and followed the Eclipse article where the SWT.EaraseItem is described as: "SWT.EraseItem: allows a client to custom draw a cell’s background and/or selection, and to influence whether the cell’s foreground should be drawn"
But this does not appear to work correctly on Linux (GTK) environments. This leads me to believe there might be a bug in its implementation for this platform.

I’ve implemented a fix/option that influences selection colors, but explicitly only for Windows and macOS, effectively skipping GTK.
I know this is not nice, but according to the amount of issues (all on windows) I guess this solution is better than doing nothing.

Any opinions?