diff --git a/interface/wx/ctrlsub.h b/interface/wx/ctrlsub.h
index 83b2035c6d..f23616e4e0 100644
--- a/interface/wx/ctrlsub.h
+++ b/interface/wx/ctrlsub.h
@@ -347,6 +347,26 @@ public:
     */
     void Delete(unsigned int n);
 
+
+    /**
+       Returns true, if either untyped data (@c void*) or object data (wxClientData*)
+       is associated with the items of the control.
+    */
+    bool HasClientData() const;
+    
+    /**
+       Returns true, if object data (wxClientData*)
+       is associated with the items of the control.
+    */
+    bool HasClientObjectData() const;
+
+    /**
+       Returns true, if untyped data (@c void*) 
+       is associated with the items of the control.
+    */
+    bool HasClientUntypedData() const;
+
+
     //@{
 
     /**