AndroidのListPopupWindowでアニメーションを消去したい

Question

material.ioのList popup window menusでリスト表示のアニメーションを消去したいのですが、listPopupWindow.animationStyle = 0とやってもうまく消えてくれません。

listPopupWindow.animationStyle = 0で、
ListPopupWindowのsetAnimationStyleが呼ばれその内部で
PopupWindowに（mPopup）setAnimationStyleでanimationStyleをセットしています。

PopupWindowのsetAnimationStyleには、ドキュメントにアニメーション無しは0(0 for no animation)と書かれています。

どなたかお知恵を頂けないでしょうか？

public class ListPopupWindow implements ShowableListMenu {

	PopupWindow mPopup;

	/**
	 * Set an animation style to use when the popup window is shown or dismissed.
	 *
	 * @param animationStyle Animation style to use.
	 */
	public void setAnimationStyle(@StyleRes int animationStyle) {
	    mPopup.setAnimationStyle(animationStyle);
	}

public class PopupWindow {

	/**
	 * <p>Change the animation style resource for this popup.</p>
	 *
	 * <p>If the popup is showing, calling this method will take effect only
	 * the next time the popup is shown or through a manual call to one of
	 * the {@link #update()} methods.</p>
	 *
	 * @param animationStyle animation style to use when the popup appears
	 *      and disappears.  Set to -1 for the default animation, 0 for no
	 *      animation, or a resource identifier for an explicit animation.
	 *
	 * @see #update()
	 */
	public void setAnimationStyle(int animationStyle) {
	    mAnimationStyle = animationStyle;
	}

class FirstFragment : Fragment() {

    override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        val view = inflater.inflate(R.layout.fragment_first, container, false)

        val listPopupWindowButton = view.findViewById<Button>(R.id.list_popup_button)
        val listPopupWindow: ListPopupWindow = ListPopupWindow(requireContext(), null, R.attr.listPopupWindowStyle)

        // Set button as the list popup's anchor
        listPopupWindow.anchorView = listPopupWindowButton

        // Set list popup's content
        val items = listOf("Option 1", "Option 2", "Option 3")
        val adapter = ArrayAdapter(requireContext(), R.layout.list_popup_window_item, items)
        listPopupWindow.setAdapter(adapter)

        // Set list popup's item click listener
        listPopupWindow.setOnItemClickListener { parent: AdapterView<*>?, view: View?, position: Int, id: Long ->
            // Respond to list popup window item click.

            // Dismiss popup.
            listPopupWindow.dismiss()
        }

        // Show list popup window on button click.
        listPopupWindowButton.setOnClickListener { v: View? -> listPopupWindow.show() }

        // アニメーションがオフにならない？？？
        listPopupWindow.animationStyle = 0

        return view
    }

layout/list_popup_window_item

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ellipsize="end"
    android:maxLines="1"
    android:padding="16dp"
    android:textAppearance="?attr/textAppearanceSubtitle1" />

fragment_first

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".FirstFragment">

    <Button
        android:id="@+id/list_popup_button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toTopOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:text="show_menu"/>

</androidx.constraintlayout.widget.ConstraintLayout>