internal bool RemoveOverlayable(Overlayable overlayable)
{
XiHelper.ArgumentNullCheck(overlayable);
return overlayablePSet.Remove(overlayable);
}
internal bool AddOverlayable(Overlayable overlayable)
{
XiHelper.ArgumentNullCheck(overlayable);
return overlayablePSet.TryAddValue(overlayable);
}