Arcgis for .net 100.1 鼠标处于按下状态，鼠标移动事件不会触发

myMapView.Map = new Map(Basemap.CreateOpenStreetMap());

myMapView.GraphicsOverlays.Add(new GraphicsOverlay());

myMapView.MouseMove += MyMapView_MouseMove;

private void MyMapView_MouseMove(object sender, MouseEventArgs e)

{

   Console.WriteLine(e.RightButton.ToString());

   Console.WriteLine(e.LeftButton.ToString());

}

当鼠标处于没有按下的状态，鼠标移动会一直输出 Released
但鼠标处于按下状态后，MouseMove事件都不会触发
要想在鼠标按下的状态触发移动事件需要设置那个字段吗？