I have a subclass of SpTablePresenter which correctly displays a list of items. It is set up to activateOnDoubleClick as I want to open another SpPresenter I have created on the selected table row using the value in the first column to complete the presenter. My SpTablePresenter headed Element Attributes is shown bottom left in the attached screenshot. The class method top right reports that valueAtColumn:row: is sent but not implemented and yet it clearly is implemented by the superclass of my presenter (and I have used the method elsewhere in my project (NB: this method is just an instrument at the moment so that I can check what is happening. Double clicking a table row executes the method openAttributeEditorOn: but the debugger reports instance of my presenter class did not understand valueAtColumn:row: So what am I doing wrong here? Advice please. Regards Bob Briggs