public function getDateFilterForm() {

		// Display a form that allows filtering from a specified date.

		$children = MediaPage::get()->filter('ParentID', $this->data()->ID);
		$form = Form::create(
			$this,
			'getDateFilterForm',
			FieldList::create(
				$date = DateField::create(
					'from',
					'From'
				)->setMinDate($children->min('Date'))->setMaxDate($children->max('Date')),
				HiddenField::create(
					'category'
				),
				HiddenField::create(
					'tag'
				)
			),
			FieldList::create(
				FormAction::create(
					'dateFilter',
					'Filter'
				),
				FormAction::create(
					'clearFilters',
					'Clear'
				)
			)
		);
		$form->setFormMethod('get');

		// Remove validation if clear has been triggered.

		$request = $this->getRequest();
		if($request->getVar('action_clearFilters')) {
			$form->unsetValidator();
		}

		// Allow extension customisation.

		$this->extend('updateFilterForm', $form);

		// Display existing request filters.

		$form->loadDataFrom($request->getVars());
		return $form;
	}