Scrolling changes with build 455 (706481)

Question

It seems something changed with scrolling from build 452 (705274) to build 455 (706481).  The below works fine in 452 (705274) but in 455 (706481) if i scroll down to the bottom i cant scroll back to the top.  I origanlly thought it was an issue with images b/c we have a lot of InlineGraphicElements and saw some comments about scrolling issues with images in the last change log but made this test and its happening without them.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application
     xmlns:mx="http://www.adobe.com/2006/mxml"
     layout="absolute"
     horizontalAlign="center"
     applicationComplete="init()">
    <mx:Script>
         <![CDATA[
             import flashx.textLayout.BuildInfo;
             import flash.utils.*;
             import flash.text.engine.*;
             import flash.display.*;
             import flash.events.*;
             import flashx.textLayout.elements.*;
             import flashx.textLayout.formats.*;
             import flashx.textLayout.container.*;
             import flashx.textLayout.events.*;
             import flashx.textLayout.edit.*;
             private var container:Sprite = null;
            public function init() : void
                 container = new Sprite;
                    textArea.rawChildren.addChild(container);
                  var textFlow:TextFlow = new TextFlow;
                  textFlow.interactionManager = new EditManager;
                  textFlow.flowComposer.addController(new ContainerController(container, textArea.width, textArea.height));
                 var i : uint = 10;
                 var total : uint = i;
                 while( i )
                     var dv : DivElement = new DivElement;
                     var sp : SpanElement = new SpanElement;
                     sp.text = i + "/" + total + " " + BuildInfo.kBuildNumber;
                     var p : ParagraphElement = new ParagraphElement;
                     p.addChild(sp);
                     dv.addChild(p)
                     textFlow.addChild( dv );
                     i--;
                   textFlow.interactionManager.setSelection(0,0);
                 textFlow.interactionManager.setFocus();
                 textFlow.flowComposer.updateAllControllers();
         ]]>
     </mx:Script>
    <mx:Canvas
         height="50"
         width="100"
         backgroundColor="#FFFFFF"
         id="textArea">   
     </mx:Canvas>
</mx:Application>

Answer 1

I got the textLayout.swc from the 4.0.0.8217 gumbo build.  I did look at the release notes http://opensource.adobe.com/wiki/display/flexsdk/changes4.0.0.8217.  Only saw something about nullTabStopFormat  and defaults possibly the change was made in another nightly build or i just missed it.  Is there a better place to look for changes?
Thanks for the heads up about the API changes.  Overall i think things have been going pretty smooth considering ive been working off weekly builds for the past 8 or 9 weeks.  You guys have also been very receptive on the forum.  Ill be ready for the API changes Monday when I update to the next weekly build.
Cheers