diff --git a/src/main/java/com/flowingcode/vaadin/addons/twincolgrid/TwinColGrid.java b/src/main/java/com/flowingcode/vaadin/addons/twincolgrid/TwinColGrid.java
index 9a1db35..4580636 100644
--- a/src/main/java/com/flowingcode/vaadin/addons/twincolgrid/TwinColGrid.java
+++ b/src/main/java/com/flowingcode/vaadin/addons/twincolgrid/TwinColGrid.java
@@ -684,6 +684,7 @@ public void setReadOnly(final boolean readOnly) {
     removeButton.setEnabled(!readOnly);
     addAllButton.setEnabled(!readOnly);
     removeAllButton.setEnabled(!readOnly);
+    setClassName("readonly", readOnly);
   }
 
   @Override