Why do i have a delay in moving Gameobjects with Microsoft Kinect using a Kinect for Windows SDK v1.8 Packet only WHEN I HAVE A MAXIMIZED WINDOW?

I have a delay using Kinect for moving simple GameObjects in Unity when MAXIMIZING the window.

For using my Kinect v2, I implemented Kinect for Windows Package, where I used the Kinect 2.0.1410.19000 Unity Package. (You can find in the link at the end of the post) The instruction according to which i worked, you can see in this great tutorial:

TUTORIAL: https://channel9.msdn.com/Blogs/2p-start/Gesture-Control-with-Kinect-and-Unity-made-easy?ocid=player

I also use the following DetectJoint Script as described in the Tutorial Video or the Blog (Link below).

 void Update ()
 {
     if (_bodySourceManager == null)
     {
         return;
     }
  
     _bodyManager = _bodySourceManager.GetComponent<BodyManager>();
     if (_bodyManager == null)
     {
         return;
     }
  
     Body[] data = _bodyManager.GetData();
     if (data == null)
     {
         return;
     }
  
     // get the first tracked body…
     foreach (var body in data)
     {
         if (body == null)
         {
             continue;
         }
  
         if (body.IsTracked)
         {
             var pos = body.Joints[_jointType].Position;
            this.gameObject.transform.position = new Vector3(pos.X, pos.Y, pos.Z);
             break;
         }
     }
 }

Now the currious part and my problem is, the tracking works very well when I play in the Unity Editor and have the game window as default or when i play in the Build with a small windowed Game. When I maximize the game in the Editor or i have the Built as fullscrenn I have a huge delay and it isn't anymore possible to play ! Where could or is this comming from??

The turorial is also linked and based on this Blog. Here you may can catch up faster.

BLOG: http://peted.azurewebsites.net/kinect-4-windows-v2-unity-3d/

Many thanks for any help or suggestens.