private void _mapControl_MouseMove(object sender, MouseEventArgs e)
 {
     if (e.RightButton != MouseButtonState.Pressed)
     {
         SelectedMarker = null;
         _drag          = false;
         _mapControl.UpperLayer.Children.Remove(_line);
         _mapControl.UpperLayer.Children.Remove(_arrow);
         _mapControl.UpperLayer.Children.Remove(_panel);
     }
     else
     {
         var pos = e.GetPosition(_mapControl.UpperLayer);
         _line.X2        = pos.X;
         _line.Y2        = pos.Y;
         CurrentPosition = _gMap.FromLocalToLatLng((int)pos.X, (int)pos.Y);
         UIHelpers.CalculateArrow(_line, _arrow);
         Canvas.SetLeft(_panel, pos.X);
         Canvas.SetTop(_panel, pos.Y - _panel.ActualHeight);
     }
 }