res/layout/restricted_preference_dropdown.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2016 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License
  -->
<FrameLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    <view android:id="@+id/spinner"
            class="com.android.settings.notification.RestrictedDropDownPreference$ReselectionSpinner"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:visibility="invisible"
            android:layout_marginStart="@dimen/preference_no_icon_padding_start"/>

    <include layout="@layout/preference_material" />

</FrameLayout>