[flexcoders] How to disapbe the datatip for HSlider?

[markflex2007]

Hi;

I want to disable to show datatip in some value for HSlider,I use thumbDrag 
event,but it seems the showDataTip not offect that.

the following is my code.

1 HSlider component

<mx:HSlider id="radius" width="300" minimum="0.5" maximum="5"
tickColor="0x323232" snapInterval="0.5" tickInterval="0.5"
dataTipPrecision="1" labels="['0.5 mile','5 miles']" liveDragging="true" 
thumbDrag="radiusAdjust()"
dataTipFormatFunction="radiusDataTipFunc" showDataTip="false"/>

2.do not show datatip for value 1.5 and 2.5

private function radiusAdjust():void{
        
        if(radius.value == 1.5 || radius.value == 2.5){
          radius.showDataTip = false;
        }else{
          radius.showDataTip = true;
        }

}

Please let me know what wrong I make for this.

Thank you for your help

Mark