onPreferenceStartScreen() is never called in PreferenceFragmentCompat on Android

First question on stackoverflow, please forgive any inconsistencies.

My Android app implements a PreferenceFragmentCompat fragment which is opened through a button click in the MainActivity. All the options in "root" PreferenceScreen work smoothly but I cannot open any "child" PreferenceScreens.

After a lot of search, I found the need to implement the onPreferenceStartScreen callback in my fragment and it did work! But now, I made quite a few changes to the app and must have screwed something up and can't figure out what.

So here it goes!

Among others, I implement these 2 libraries in my app level gradle.build

implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'androidx.preference:preference:1.1.1'

This is my test pref3.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:defaultValue="false"
        android:key="check_box_preference_1"
        android:title="Check box preference" />
    <PreferenceScreen android:title="Preference Screen">
        <CheckBoxPreference
            android:defaultValue="false"
            android:key="check_box_preference_2"
            android:title="Check box preference" />
    </PreferenceScreen>
</PreferenceScreen>

This is my test java Preferences fragment (Common.log is my utility logger method)

public class TestPrefFrag extends PreferenceFragmentCompat implements PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
    private static final String TAG = "TestPrefFrag";

    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        Common.log(5, TAG, "onCreatePreferences: started");
        setPreferencesFromResource(R.xml.prefs3, rootKey);

    }

    @Override
    public boolean onPreferenceStartScreen(PreferenceFragmentCompat caller, PreferenceScreen preferenceScreen) {
        Common.log(5, TAG, "onPreferenceStartScreen: '" + caller.getTag() + "' called for key '" + preferenceScreen.getKey() + "'");
        caller.setPreferenceScreen(preferenceScreen);
        return true;
    }

    @Override
    public void onNavigateToScreen(PreferenceScreen preferenceScreen) {
        Common.log(5, TAG, "onNavigateToScreen: called for key '" + preferenceScreen.getKey() + "'");
        //getCallbackFragment();
        super.onNavigateToScreen(preferenceScreen);
    }

    @Override
    public boolean onPreferenceTreeClick(Preference preference) {
        Common.log(5, TAG, "onPreferenceTreeClick: detected click @ '" + preference.getKey() + "'");
        return super.onPreferenceTreeClick(preference);
    }
}

When I run this

• clicking the CheckBoxPreference in the root screen calls the onPreferenceTreeClick only
• clicking the PreferenceScreen in the root screen calls the onNavigateToScreen and then the onPreferenceTreeClick but never the onPreferenceStartScreen

Shouldn't onPreferenceStartScreen be called right after onNavigateToScreen. What am I doing wrong?

Thanks for any help!

You need to override the PreferenceFragment method getCallbackFragment, like this

@Override
public Fragment getCallbackFragment() {
    return this;
}