diff --git a/include/wx/cocoa/dialog.h b/include/wx/cocoa/dialog.h
index 38038b341c..e736b8f756 100644
--- a/include/wx/cocoa/dialog.h
+++ b/include/wx/cocoa/dialog.h
@@ -74,6 +74,8 @@ protected:
 // ------------------------------------------------------------------------
 protected:
     virtual void Cocoa_close(void);
+    virtual bool Cocoa_canBecomeMainWindow(bool &canBecome)
+    {   canBecome = true; return true; }
 
 // ------------------------------------------------------------------------
 // Implementation