Multiline text displayed with mx:Text, text moves up by one line when selected and drag down

This is the original method find from the framework

    /**
     *  @private
     */
    override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
    {
        // Don't call super.updateDisplayList();
        // Text has a different layout algorithm than Label.
        if (isSpecialCase())
        {
            var firstTime:Boolean = isNaN(lastUnscaledWidth) || lastUnscaledWidth != unscaledWidth;
            lastUnscaledWidth = unscaledWidth;
            if (firstTime)
            {
                invalidateSize();
                return;
            }
        }

        // The textField occupies the entire Text bounds minus the padding.
        var paddingLeft:Number = getStyle("paddingLeft");
        var paddingTop:Number = getStyle("paddingTop");
        var paddingRight:Number = getStyle("paddingRight");
        var paddingBottom:Number = getStyle("paddingBottom");
        textField.setActualSize(unscaledWidth - paddingLeft - paddingRight,
                                unscaledHeight - paddingTop - paddingBottom);

        textField.x = paddingLeft;
        textField.y = paddingTop;
        // Although we also set wordWrap in commitProperties(), we do
        // this here to handle width being set through setActualSize().
        if (Math.floor(width) < Math.floor(measuredWidth))
            textField.wordWrap =  true;

}

this custom component extent and override class for mx:Text component

override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void
        {

            // The textField occupies the entire Text bounds minus the padding.
            var paddingLeft:Number = getStyle("paddingLeft");
            var paddingTop:Number = getStyle("paddingTop");
            var paddingRight:Number = getStyle("paddingRight");
            var paddingBottom:Number = getStyle("paddingBottom");
            var leading:Number = getStyle("leading");

            textField.setActualSize(unscaledWidth - paddingLeft - paddingRight,unscaledHeight - paddingTop - paddingBottom + leading);

            textField.x = paddingLeft;
            textField.y = paddingTop;
            // Although we also set wordWrap in commitProperties(), we do
            // this here to handle width being set through setActualSize().
            if (Math.floor(width) < Math.floor(measuredWidth))
                textField.wordWrap =  true;
        }