- Take care with `stageChildren()` overrides. `Hierarchy::numChildren() ` results will only make use of `stageChildren()` customisations that are applied to the base class and don't include record-specific behaviour.
GridFields now default to using the new search UI which uses [SilverStripe's FormSchema API](https://api.silverstripe.org/master/SilverStripe/Forms/Schema/FormSchema.html).
If you would rather continue using the old search API, you can remove the default `GridFieldFilterHeader` from your GridField configuration and replace with one whose _legacy_ flag has been enabled.
To enable legacy mod on a `GridFieldFilterHeader`, just pass `true` to the first argument of its constructor.