/// Is the ceiling being visualized by the boundary system.
/// </summary>
/// <remarks>
/// The boundary system defines the ceiling as a plane set at <see cref="Microsoft.MixedReality.Toolkit.Boundary.IMixedRealityBoundarySystem.BoundaryHeight"/> above the floor.
/// <param name="eventSystem">Typically will be <see href="https://docs.unity3d.com/ScriptReference/EventSystems.EventSystem-current.html">EventSystems.EventSystem.current</see></param>
/// <param name="eventSystem">Typically will be <see href="https://docs.unity3d.com/ScriptReference/EventSystems.EventSystem-current.html">EventSystem.current</see></param>