How do I change a custom cursor to the default using the Animate CC 2017 flash code?

If there is no other code than what you showed, the timeline would have gone quickly onto the Mouse.show() frame. You would normally have a stop() somewhere, and only go on to the Mouse.show() when you're finished with the custom cursor.

Also, if there is anything inside the scope sight that might trap the mouse click you ought to set mouseChildren to false.

Here are scripts I just tested, and the initial frame:

scope1.mouseEnabled = false;

scope1.mouseChildren = false;

scope1.visible = true;

scope1.addEventListener(Event.ENTER_FRAME, fl_CustomMouseCursor);

stage.addEventListener(MouseEvent.CLICK, clicked);

function fl_CustomMouseCursor(e: Event) {

  scope1.x = stage.mouseX;

  scope1.y = stage.mouseY;

}

function clicked(e: MouseEvent) {

  stage.removeEventListener(MouseEvent.CLICK, clicked);

  scope1.removeEventListener(Event.ENTER_FRAME, fl_CustomMouseCursor);

  play();

}

Mouse.hide();

stop();

and on a frame after that, which is reached because to the play() line:

Mouse.show();

scope1.visible = false;

stop();