OOUI bad alignment

    static function buildFilterLoader() {
        $loadText =
        new OOUI\FieldLayout(
            new OOUI\TextInputWidget(
                [
                    'type' => 'number',
                    'name' => 'wpInsertFilter',
                    'id' => 'mw-abusefilter-load-filter'
                ]
            ),
            ['label' => wfMessage( 'abusefilter-test-load-filter' )->text()]
            );
        $loadButton =
            new OOUI\ButtonInputWidget(
                [
                    'label' => wfMessage( 'abusefilter-test-load' )->text(),
                    'id' => 'mw-abusefilter-load'
                ]
            );

        $loadGroup =
        new OOUI\HorizontalLayout( [
        'items' =>
                [$loadText, $loadButton]
        ]);
        // CSS hack to avoid huge input field
        $loadDiv =
            Xml::tags(
                'div',
                [ 'class' => 'mw-abusefilter-OOUI-smaller' ],
                $loadGroup
            );
        return $loadDiv;
    }