 		public const horizontalMode:LinkableBoolean = registerSpatialProperty(new LinkableBoolean(false));
 		public const zoomToSubset:LinkableBoolean = registerSpatialProperty(new LinkableBoolean(true));
 		public const zoomToSubsetBars:LinkableBoolean = registerSpatialProperty(new LinkableBoolean(false));
-		public const barSpacing:LinkableNumber = registerSpatialProperty(new LinkableNumber(0));
+		public const barSpacing:LinkableNumber = registerLinkableChild(this, new LinkableNumber(0));
 		public const groupingMode:LinkableString = registerSpatialProperty(new LinkableString(STACK, verifyGroupingMode));
 		public static const GROUP:String = 'group';
 		public static const STACK:String = 'stack';

				sortedIndex = _binnedSortColumn.getValueFromKey(recordKey, Number);
			else
				sortedIndex = _sortedIndexColumn.getValueFromKey(recordKey, Number);
			var spacing:Number = StandardLib.constrain(barSpacing.value, 0, 1) / 2; // max distance between bar groups is 0.5 in data coordinates
			var minPos:Number = sortedIndex - 0.5 + spacing / 2;
			var maxPos:Number = sortedIndex + 0.5 - spacing / 2;
			var recordWidth:Number = maxPos - minPos;

			
			// get the sorted keys
			var sortedKeys:Array = _sortedIndexColumn.keys;
			var sortedKeyIndex:int = Math.round(value);
			if (sortedKeyIndex != value || sortedKeyIndex < 0 || sortedKeyIndex > sortedKeys.length - 1)
				return '';
			
			// if the labelColumn doesn't have any data, use default label
			if (labelColumn.getInternalColumn() == null)
