diff --git a/bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/CSSEngineHelper.java b/bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/CSSEngineHelper.java
index 5020081f6de..1d9eab04cd6 100644
--- a/bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/CSSEngineHelper.java
+++ b/bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/CSSEngineHelper.java
@@ -25,8 +25,8 @@
  * used by renderers.
  */
 public class CSSEngineHelper {
-	private IEclipseContext context;
-	private Control control;
+	private final IEclipseContext context;
+	private final Control control;
 	private IStylingEngine engine;
 	private CSSStyleDeclaration style;