Cannot remove focus on spark.skins.mobile.TextAreaSkin

Hi,

I am trying to remove the focus of a spark.skins.mobile.TextAreaSkin but
this doesn't work...

My Code:

import de.assets.ChatTextFieldBackground;
import de.assets.ChatTextFieldBackgroundBorder;

import spark.skins.mobile.TextAreaSkin;

public class LeagueBoardTextAreaSkin extends TextAreaSkin

private var background:ChatTextFieldBackground;

public function LeagueBoardTextAreaSkin()

super();

measuredDefaultHeight = 50;

setStyle("paddingTop", 10);
setStyle("paddingBottom", 25);
setStyle("paddingLeft", 10);
setStyle("paddingRight", 10);

setStyle("borderStyle", "none");
setStyle("borderSkin", null);
setStyle("focusSkin", null);

setStyle("focusAlpha", 0);
setStyle("focusThickness", 0);

setStyle("dropShadowEnabled", false);
setStyle("dropShadowVisible", false);
setStyle("dropShadowColor", 0x00FF00);setStyle("shadowDistance", 20);
setStyle("highlightColor", 0x00FF00);
setStyle("focusRoundedCorners", 20);

setStyle("borderVisible", false);
setStyle("errorSkin", null);
setStyle("focusSkin", null);

focusRect = null;

override protected function createChildren():void

super.createChildren();
background = new ChatTextFieldBackground();
addChildAt(background, 0);

/**
* @private
*/
override protected function drawBackground(unscaledWidth:Number,
unscaledHeight:Number):void

background.setLayoutBoundsSize(unscaledWidth, unscaledHeight);

override public function drawFocus(isFocused:Boolean):void

super.drawFocus(false);

Any idea what I have to do to get rid of the blue
focus-highlight-dropShadow-Thing?

Best regards,

Christian