Enable and Disable drag jQuerz

I have got chart in container and checkbox for dragging function, enable and disable works, but if i click for second time enable checkbox it doesn't work. I don't know where is mistake. Below is jiddle url and IF statement function Thanks for suggests

http://ift.tt/2o62Okc

function EnableDrag(checkboxvalue) {
  if (checkboxvalue == true) {
    $("#chartdiv").draggable("enable");
  } else {
    $("#chartdiv").draggable("disable");
  }
}