Drag on touch screen and change value

Hi
on the attached patch I am trying to do a drag and move action for a touch display application. I am stuck at setting a limit on the max range of the movement, which I can solve with some weird serie of switch nodes but I think there should be a more elegant solution. Any hint?
S.

drag and change.v4p (18.9 kB)

Just put the Framedelay below the MapRange.