public void MouseEnter(ViewportEvent e)
 {
     Focus = true;
 }
 public void DragEnd(ViewportEvent e)
 {
 }
 public void DragMove(ViewportEvent e)
 {
 }
 public void DragStart(ViewportEvent e)
 {
 }
 public void MouseUp(ViewportEvent e)
 {
     SetFreeLook();
 }
 public void KeyUp(ViewportEvent e)
 {
     SetFreeLook();
 }