diff --git a/bundles/org.eclipse.ui.themes/css/e4-dark_linux.css b/bundles/org.eclipse.ui.themes/css/e4-dark_linux.css
index a3a738d2b8d..b3deba083ed 100644
--- a/bundles/org.eclipse.ui.themes/css/e4-dark_linux.css
+++ b/bundles/org.eclipse.ui.themes/css/e4-dark_linux.css
@@ -108,9 +108,9 @@ CTabFolder[style~='SWT.DOWN'][style~='SWT.BOTTOM'] {
     swt-selected-highlight-top: false;
 }
 
-.MPart Form Composite,
-.MPart Form Composite Tree,
-.MPartStack.active .MPart Form Composite Tree
+.Editor Form Composite,
+.Editor Form Composite Tree,
+.MPartStack.active .Editor Form Composite Tree
 {
 	background-color: #1E1F22;
 }
diff --git a/bundles/org.eclipse.ui.themes/css/e4-dark_mac.css b/bundles/org.eclipse.ui.themes/css/e4-dark_mac.css
index 2bb33eab710..8154d365509 100644
--- a/bundles/org.eclipse.ui.themes/css/e4-dark_mac.css
+++ b/bundles/org.eclipse.ui.themes/css/e4-dark_mac.css
@@ -94,9 +94,9 @@ CTabFolder[style~='SWT.DOWN'][style~='SWT.BOTTOM'] {
     swt-selected-highlight-top: false;
 }
 
-.MPart Form Composite,
-.MPart Form Composite Tree,
-.MPartStack.active .MPart Form Composite Tree
+.Editor Form Composite,
+.Editor Form Composite Tree,
+.MPartStack.active .Editor Form Composite Tree
 {
 	background-color: #1E1F22;
 }
diff --git a/bundles/org.eclipse.ui.themes/css/e4-dark_win.css b/bundles/org.eclipse.ui.themes/css/e4-dark_win.css
index a2ba03abeee..00164a24483 100644
--- a/bundles/org.eclipse.ui.themes/css/e4-dark_win.css
+++ b/bundles/org.eclipse.ui.themes/css/e4-dark_win.css
@@ -176,9 +176,9 @@ CTabFolder[style~='SWT.DOWN'][style~='SWT.BOTTOM'] {
     swt-selected-highlight-top: false;
 }
 
-.MPart Form Composite,
-.MPart Form Composite Tree,
-.MPartStack.active .MPart Form Composite Tree
+.Editor Form Composite,
+.Editor Form Composite Tree,
+.MPartStack.active .Editor Form Composite Tree
 {
 	background-color: #1E1F22;
 }