diff --git a/otk/messagedialog.hh b/otk/messagedialog.hh
index f49b4593..4a152bd4 100644
--- a/otk/messagedialog.hh
+++ b/otk/messagedialog.hh
@@ -22,6 +22,9 @@ public:
     {}
   inline const ustring& label() const { return _label; }
   inline const bool& isDefault() const { return _default; }
+
+  bool operator==(const DialogButton &o) { return _label == o._label; }
+  bool operator!=(const DialogButton &o) { return !(_label == o._label); }
 };
 
 class MessageDialog : public Widget {