[flexcoders] Where did the value go?

[justSteve]

I have a  datagrid that should send it's selectItem value to a detail form.

        <mx:DataGrid
                selectedItem="{selectedSlide}"
                change="selectSlide(event.target.selectedItem as Slide)"
                dataProvider="{slides}" >

Placing a breakpoint on the change property and observing the
event.target.selectedItem value shows the event is carrying the
expected info. But when execution reaches the handler:

        public var selectedSlide:Slide;
        private function selectSlide(pSlide:Slide):void
        {
                selectedSlide = pSlide ;  // pSlide is now null.
                dispatchEvent(new Event(SELECT, true));
        }

the param is null. How do I go about figuring out where my error is? I
reason that if there's something wrong with how I've typed 'Slide' I'd
get a compile-time error.

many thankx
--steve...