Hi joshua odell,
Thanks to your feedback we have decided to reimplement the way NumericUpDown handles input. There are just too many cases to filter specific key codes as the virtual key table sometimes varies in different laptop manufacturers. From SP2 on, that should be available later today, you will not have to worry about laptop vs desktop input or any of the sort, since the filtering is done after the textbox is updated. Of course this is done internally, and you will not notice any flickering of the textbox if typing correct or incorrect value. We have spend great amount of time testing all cases, but if you once again happen to experience the same issue please get back to us immediately, and your case will be resolved on the spot.
Thank you for contacting us, and providing us with such a great feedback!
the Telerik team