skeleton and nullreferenceexception

Question

skeleton is not being created in the following segment. I just updated to Beta 2. Normally, I don't believe SetColor is called until a skeleton is being tracked (SetColor creates an object of skeleton.Joints[...], this initialization throws the null reference exception). Now SetColor is called too early.

 

void nui_SkeletonFrameReady(object sender, SkeletonFrameReadyEventArgs e)
        {
            
            SkeletonFrame allSkeletons = e.SkeletonFrame;

            //get the first tracked skeleton

	    // skeleton SkeletonData reference is global	
            skeleton = (from s in allSkeletons.Skeletons
                                     where s.TrackingState == SkeletonTrackingState.Tracked
                                     select s).FirstOrDefault();
            
            // set background color
            SetColor(proportion, skeleton);

        }

 

there are six skeletons in allSkeletons.Skeletons and none are being tracked. shouldn't this loop through skeletons until it sees that one is being tracked? just to reiterate, I just switched to Beta 2.

Thanks for the help.