HRule stroke color
<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" verticalGap="25"> <mx:RichTextEditor id="myEditor" title="My Rich Text Editor"/> <mx:HRule strokeColor="#000000" width="{myEditor.width}"/> <mx:Text text="{myEditor.htmlText}" width="400"/> </mx:Application>