protected Designator_SelectableThings()
        {
            var highlighter = new MapCellHighlighter(SelectHighlightedCells);
            Action <CellRect> clearHighlightedCells = r => highlighter.ClearCachedCells();

            Dragger.SelectionStart    += clearHighlightedCells;
            Dragger.SelectionChanged  += clearHighlightedCells;
            Dragger.SelectionComplete += clearHighlightedCells;
            Dragger.SelectionUpdate   += r => highlighter.DrawCellHighlights();
        }
 private void ClearCurrentSelection()
 {
     currentSelection   = CellRect.Empty;
     lastSelectionStart = IntVec3.Zero;
     highlighter.ClearCachedCells();
 }