How does the Grails tag `fieldValue` perform its formatting?

I have an domain class with an `Double` attribute.

```
class Thing {
    Double numericValue
}

```

In GSP, the `fieldValue` is used (as created by `grails generate-all`) for rendering:

```
${fieldValue(bean:thing, field:"numericValue")}

```

Unfortunately digits after 3 decimal places are not displayed (ie, 0.123456 is displayed as 0.123). How do I control `fieldValue`'s formatting?

Note that I could just use `${thing.numericValue}` (which does no formatting) or 
`<g:formatNumber>`, but I'd rather use the `fieldValue` tag and specify the formatting. I just don't know where to specify `fieldValue`'s formatting.