diff --git a/bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/dom/Measure.java b/bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/dom/Measure.java
index 6a1b552..4bd8481 100644
--- a/bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/dom/Measure.java
+++ b/bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/dom/Measure.java
@@ -82,6 +82,8 @@
 			return CSS_CM;
 		case LexicalUnit.SAC_EM:
 			return CSS_EMS;
+		case LexicalUnit.SAC_EX:
+			return CSS_EXS;
 		case LexicalUnit.SAC_INCH:
 			return CSS_IN;
 		case LexicalUnit.SAC_STRING_VALUE: