Arduino absolute Positioning

I found an examle but I can't understand MouseTo.setTarget(x,y) function. If I remove the second while then it doesn't works. If I use thiw code then cursor goes to (400,100) on screen then after 1 second it returns on (0.0) and then again on (400,100)
thanks for your help

#include <Mouse.h>

#include <MouseTo.h>

const byte pin = 6;

void setup() {
  Mouse.begin();
  MouseTo.setCorrectionFactor(1);
  MouseTo.setScreenResolution(800,800);
  pinMode(pin, INPUT_PULLUP);
}

void loop() {
  while (digitalRead(pin) == LOW) {
    MouseTo.setTarget(400, 100);
    while (MouseTo.move() == false) {}
    delay(1000);
  
     }
}