jmclean/datagrid/src/DataTipNullBindling.mxml

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
			   xmlns:s="library://ns.adobe.com/flex/spark" 
			   xmlns:mx="library://ns.adobe.com/flex/mx" initialize="init(event)">
	<s:layout>
		<s:VerticalLayout />
	</s:layout>
	
	<fx:Script>
		<![CDATA[
			import mx.collections.ArrayCollection;
			import mx.events.FlexEvent;
			
			/*
			* ISSUE: data tips show for all lines when showDataTips="true" and should only show up for long lines
			*
			* WORKAROUND: dataTipField="{null}" in MXML or adg.dataTipField = null in AS
			*
			* Note mx:DataGrid and mx:List have the same issue
			*/
			
			[Bindable] public var strings:ArrayCollection = new ArrayCollection(["one","two","a long line for the number three","four","five","six","seven","eight","nine","ten"]);		
			[Bindable] public var objects:ArrayCollection = new ArrayCollection();
			
			protected function init(event:FlexEvent):void {
				for each (var label:String in strings) {
			 		objects.addItem({label:label});
				}
			}			
		]]>
	</fx:Script>
	
	<mx:AdvancedDataGrid dataProvider="{strings}" showDataTips="true" dataTipField="{null}" />
	
	<mx:DataGrid dataProvider="{strings}" showDataTips="true" dataTipField="{null}" />
	
	<mx:List dataProvider="{strings}" showDataTips="true" dataTipField="{null}" />
	
</s:Application>