Panel position and size

I don't think you can set the position of a custom panel. It seems to open where ever it was last closed. But you can set the size.

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" creationComplete="init()"
     paddingLeft="0" paddingBottom="0" paddingRight="0" paddingTop="0" 
     verticalScrollPolicy="off" horizontalScrollPolicy="off" 
     horizontalGap="0" verticalGap="1">
     <mx:Script>
          <![CDATA[
               import com.adobe.csxs.core.CSXSInterface;
               import com.adobe.csxs.events.*;
               import com.adobe.csxs.types.*;
               
               private function getGeometry():WindowGeometry {
                    var panel_X:Number = 100;
                    var panel_Y:Number = 100;
                    var panel_W:Number = windowsizebox.width + 15;
                    var panel_H:Number = windowsizebox.height + 20;
                    var windowsize:WindowGeometry = new WindowGeometry(panel_X,panel_Y,panel_W,panel_H);
                    return windowsize;
               }
               private function setSize():void{
                    var csxs:CSXSInterface = CSXSInterface.getInstance();  
                    csxs.requestStateChange(StateChangeEvent.WINDOW_RESIZE, getGeometry());
               }
               /**
                    Function:          init
                    Description:     Initialize the panel
                                        
               */
               public function init():void{
                    try{// for skinning 
                         var result:SyncRequestResult = CSXSInterface.instance.getHostEnvironment();
                         var hostData:HostEnvironment = result.data;
                         var skinInfo:AppSkinInfo = hostData.appSkinInfo;
                         var defaultColor:String = skinInfo.panelBackgroundColor.color.rgb;
                         this.setStyle("backgroundGradientColors", [defaultColor, defaultColor]);
                         this.setStyle("fontFamily", skinInfo.baseFontFamily);
                         this.setStyle("fontSize", skinInfo.baseFontSize);          
                    }catch (errObject:Error) {}
               }
          
          ]]>
     </mx:Script>
     <mx:VBox x="10" y="10" id="windowsizebox"  height="100" width="100">
          <mx:Button label="Button" click="setSize();"/>
     </mx:VBox>

</mx:Application>