Make your movable point, A, using sliders. Make a second immovable point using same sliders. Make a number, say n, in the CL linked to the submit press count. Use that to conditionally display the movable point.
A=(x1,y1 {n=0}) (Drag should be on)
B=(x1,y1) (Drag should be off)
Graph CL:
number(`n`): button.pressCount