Flex chart datatip position

I have created my own dataTipRenderer for a PlotChart and I am trying to change the position at which it is displayed. I have tried:

this.x -= (some 开发者_JS百科number);
this.y -= (some number);

Ive tried putting this code in the updateDisplayList function and when I set the data, but that didnt seem to move the datatip at all.

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need to override the move(x, y) function since this is called externally to set the location after the object's data object is set.

override public function move(x:Number, y:Number):void
{
    super.move(x - 17, y - 40);
}