diff --git a/bundles/org.eclipse.ui.themes/css/e4_default_gtk.css b/bundles/org.eclipse.ui.themes/css/e4_default_gtk.css
index 9e658422970..195c9a78739 100644
--- a/bundles/org.eclipse.ui.themes/css/e4_default_gtk.css
+++ b/bundles/org.eclipse.ui.themes/css/e4_default_gtk.css
@@ -190,7 +190,7 @@ CTabFolder Canvas {
 }
 
 .MPartStack{
-	swt-selected-tab-highlight: #a0a0a0;
+	swt-selected-tab-highlight: #8a8a8a;
 	swt-selected-highlight-top: false;
 }
 
diff --git a/bundles/org.eclipse.ui.themes/css/e4_default_win.css b/bundles/org.eclipse.ui.themes/css/e4_default_win.css
index 34e2ac72b0e..5b29c031379 100644
--- a/bundles/org.eclipse.ui.themes/css/e4_default_win.css
+++ b/bundles/org.eclipse.ui.themes/css/e4_default_win.css
@@ -165,7 +165,7 @@ CTabFolder Canvas {
 }
 
 .MPartStack{
-	swt-selected-tab-highlight: '#org-eclipse-ui-workbench-SECONDARY_BACKGROUND';
+	swt-selected-tab-highlight: #8a8a8a;
 	swt-selected-highlight-top: false;
 }