gary? Do you have surgeon knife? Because I do not see why slider need to depend on that wonderfully designed code. use: cachedSelector orMakeModelSelectorFor: selectorBody in: selectorBlock | selector | model ifNil: [^ nil]. cachedSelector ifNil: ["Make up selector from slotname if any" selector := (slotName ifNil: [selectorBody] ifNotNil: [slotName , selectorBody]) asSymbol. (model class canUnderstand: selector) ifFalse: [(self confirm: 'Shall I compile a null response for' , Character cr asString , model class name , '>>' , selector) ifFalse: [self halt]. model class compile: (String streamContents: [:s | selector keywords doWithIndex: [:k :i | s nextPutAll: k , ' arg' , i printString]. s cr; nextPutAll: '"Automatically generated null response."'. s cr; nextPutAll: '"Add code below for appropriate behavior..."'.]) classified: 'input events' notifying: nil]] ifNotNil: [selector := cachedSelector]. ^ selectorBlock value: selector