You need value binding to the data property
<mx:NumericStepper stepSize="0.01" minimum="0" maximum="99999999" dataChange="outerDocument.debug(event)" value={data} > or... set the itemEditor of the datagrid to be a class factory which generates NumericSteppers with the factory’s properties set up. Something like (off top of head, so probably won’t compile) private function creationCompleteHandler() : void { var itemFactory : ClassFactory = new ClassFactory(NumericStepper); itemFactory.properties = {maximum:99999999, minimum:0, setpSize:0.01}; dgc.itemEditor = itemFactory; } When the Stepper is used directly, rather than being wrapped in a mx:Component, it picks it up directly as the set data(...) is being called on the NumericStepper and not the wrapper component. Gk.