+ wxWindow* m_extraControl;
+
+ // returns true if control is created (if it already exists returns false)
+ bool CreateExtraControl();
+ // return true if SetExtraControlCreator() was called
+ bool HasExtraControlCreator() const
+ { return m_extraControlCreator != NULL; }
+ // get the size of the extra control by creating and deleting it
+ wxSize GetExtraControlSize();