[flexcoders] how can I get a popupButton's popUp to resize while popped up?

[Pan Troglodytes]

Okay, so given the following application:

<?xml version="1.0" encoding="utf-8"?>
<Application
  xmlns="http://www.adobe.com/2006/mxml";
  >
  <Script>
    <![CDATA[
      private function addCategory():void
      {
        var gi:GridItem;
        var gr:GridRow = new GridRow;

        gi = new GridItem;
        (gi.addChild(new Label) as Label).text = "item " + (grid.numChildren
- 3) + ":";
        gr.addChild(gi);

        gi = new GridItem;
        (gi.addChild(new Label) as Label).text = "value";
        gr.addChild(gi);

        grid.addChildAt(gr, grid.numChildren - 2);
      }
    ]]>
  </Script>
  <PopUpButton openAlways="true">
    <popUp>
      <Grid id="grid" paddingTop="4" paddingBottom="4" paddingLeft="4"
paddingRight="4"
        fontSize="12" backgroundColor="0xFFFFFF" borderStyle="outset"
borderThickness="2"
        >
        <GridRow>
          <GridItem colSpan="3">
            <CheckBox label="Categorize data" fontWeight="bold"/>
          </GridItem>
        </GridRow>
        <GridRow>
          <GridItem>
            <Label text="Start:"/>
          </GridItem>
          <GridItem>
            <Label text="first row"/>
          </GridItem>
        </GridRow>
        <GridRow id="lastRow">
          <GridItem>
            <Label text="End:"/>
          </GridItem>
          <GridItem>
            <Label text="last row"/>
          </GridItem>
        </GridRow>
        <GridRow>
          <GridItem colSpan="3">
            <Button label="Add Category" click="addCategory()"/>
          </GridItem>
        </GridRow>
      </Grid>
    </popUp>
  </PopUpButton>
</Application>

I want to be able to click the popupButton, click the "Add Category" button,
and have the popped up window resize right then so you can see everything.
Is there a good way (or even an ok way) to do this?

-- 
Jason