diff --git a/lib/src/retained/element_mouse_event_args.dart b/lib/src/retained/element_mouse_event_args.dart
index b505229b..db6ec32e 100644
--- a/lib/src/retained/element_mouse_event_args.dart
+++ b/lib/src/retained/element_mouse_event_args.dart
@@ -8,7 +8,7 @@ class ElementMouseEventArgs extends EventArgs {
     assert(element != null);
     assert(mouseEvent != null);
 
-    return new ElementMouseEventArgs._internal(element, mouseEvent.shiftKey);
+    return new ElementMouseEventArgs._internal(element, (mouseEvent.button == 2));
   }
 
   ElementMouseEventArgs._internal(this.element, this.shiftKey);