private void Subscribe_MouseDown(MouseDetails mouseDetails)
 {
     Append("mouse down: " + mouseDetails.ToString());
 }
 private void Subscribe_MouseClickAt(MouseDetails mouseDetails)
 {
     Append("mouse click: " + mouseDetails.ToString());
 }
 private void Subscribe_MouseUp(MouseDetails mouseDetails)
 {
     Append("mouse up: " + mouseDetails.ToString());
 }