Add newline as well as more clarifying comments to Slider field.

Author: Julia Schwarz

Assets/MixedRealityToolkit.SDK/Features/UX/Scripts/Sliders/SliderEventData.cs

@@ -33,8 +33,10 @@ public SliderEventData(float o, float n, IMixedRealityPointer pointer, PinchSlid
 
         /// <summary>
         /// The currently active pointer manipulating / hovering the slider,
-        /// or null if no pointer is manipulating the slider
+        /// or null if no pointer is manipulating the slider.
+        /// Note: OnSliderUpdated is called with .Pointer == null
+        /// OnStart, so always check if this field is null before using!
         /// </summary>
         public IMixedRealityPointer Pointer { get; set; }
     }
-}
+}