I can't agree with that. The AfterUpdate event fires after a selection is made - even if you pick the same value that is already been selected. At least it does for me.
Suggest you put msgbox "After update fired" as the first line of code, save, switch back to form view and make a selection. If there's no message, then the control might be corrupt. Or, you are using the AfterUpdate event for the form itself. That's why posting the code might be important to getting a resolution.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.