 		private var _progress:Number = 0;
 		private var _delayInit:Boolean = false;
 		private var _pendingInit:Boolean = false;
-		private var _keyToSortIndex:Dictionary;
 		
 		/**
 		 * This function must be called to set the size of the BitmapData buffer.

				_unscaledHeight = height;
				_dependencies.triggerCallbacks();
			}
		}
		
		private function handleKeySetChange():void
		{
			// save a lookup from key to sorted index
			// this is very fast
			_keyToSortIndex = new Dictionary(true);
			var sorted:Array = _plotter.filteredKeySet.keys;
			for (var i:int = sorted.length; i--;)
				_keyToSortIndex[sorted[i]] = i;
		}
		private function cachedKeyCompare(key1:IQualifiedKey, key2:IQualifiedKey):int
		{
			return ObjectUtil.numericCompare(_keyToSortIndex[key1], _keyToSortIndex[key2]);
		}
		
		/**

			for each (var dependency:ILinkableObject in list)
				registerLinkableChild(_dependencies, dependency);
			
			_dependencies.addImmediateCallback(this, asyncStart, true);
			
			linkBindableProperty(_layerSettings.visible, completedBitmap, 'visible');
