jumping text issue in RichEditableText

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009" 
                            xmlns:s="library://ns.adobe.com/flex/spark" 
                            xmlns:mx="library://ns.adobe.com/flex/mx"
                            creationComplete="windowedapplication1_creationCompleteHandler(event)">
     <fx:Script>
          <![CDATA[
               import flashx.textLayout.formats.LineBreak;
               import mx.events.FlexEvent;
               import spark.components.RichEditableText;               
               
               private var newTextComponent:RichEditableText;
                         
               protected function windowedapplication1_creationCompleteHandler(event:FlexEvent):void
               {
                    var tm:TextLineMetrics;
                    newTextComponent = new RichEditableText();
                    borderContainerID.addElement(newTextComponent);
                    newTextComponent.text = "Hello";
                    newTextComponent.height = 50
                    newTextComponent.setStyle("lineBreak",LineBreak.EXPLICIT);
                    newTextComponent.textFlow.fontSize = 70;
                    newTextComponent.textFlow.color = 0xFF0000;
                    newTextComponent.multiline = true;
               }
               
          ]]>
     </fx:Script>
     <fx:Declarations>
          <!-- Place non-visual elements (e.g., services, value objects) here -->
     </fx:Declarations>
     
     <s:BorderContainer id="borderContainerID" backgroundColor="#eeeeee" width="100%" height="70">
          <s:layout>
               <s:VerticalLayout/>
          </s:layout>          
     </s:BorderContainer>
</s:WindowedApplication>