internal void RemoveFromSelection(SelectableObject selectableObject)
 {
     selectableObject.revertHighlight();
     selectableObject.resetToParentGroup();
     SketchObjectsOfSelection.Remove(selectableObject);
 }
#pragma warning restore CS0649

        internal void AddToSelection(SelectableObject selectableObject)
        {
            SketchObjectsOfSelection.Add(selectableObject);
        }