Some users have wondered what the action “cancel motion sensor actions” really does. You find this action in the configuration of a switch like the Hue Dimmer Switch.
The action “cancel motion sensor actions” is intended for those situations when you want to temporarily suppress a motion response when there is no movement. In other words so that the lights do not switch off when you walk away from the location of this motion sensor.
Here is an example to explain this further:
Suppose you have a bathroom with a glass shower room inside. A motion sensor does not respond through glass. When you are in the shower, there is no movement for the motion sensor, and the motion sensor will respond to no-motion actions. Those are the actions on the no-motion tab.
When you walk into the shower you do not want the lights to switch off as long as you stay in there. So you program the button of, for example, a hue dimmer switch with the action “cancel motion sensor actions”. When you press that button, the motion sensor will not switch off the lights because the action has been canceled by your button press.
When you stay in the room with the motion sensor in it (so in the bathroom), it will detect movement again and therefore will start carrying out actions again. Walking away from the shower or walking out of the bathroom immediately results in no further actions and the light will stay on.