diff --git a/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorFragment.kt b/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorFragment.kt
index 1d262d405c..7ef1bdd98e 100644
--- a/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorFragment.kt
+++ b/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorFragment.kt
@@ -45,12 +45,12 @@ import timber.log.Timber
  * To use this [Fragment], create a factory with [PdfNavigatorFactory.createFragmentFactory].
  */
 @ExperimentalReadiumApi
-class PdfNavigatorFragment<S : Configurable.Settings, P : Configurable.Preferences<P>, E : PreferencesEditor<P>> internal constructor(
+class PdfNavigatorFragment<S : Configurable.Settings, P : Configurable.Preferences<P>> internal constructor(
     override val publication: Publication,
     initialLocator: Locator? = null,
     initialPreferences: P,
     private val listener: Listener?,
-    private val pdfEngineProvider: PdfEngineProvider<S, P, E>
+    private val pdfEngineProvider: PdfEngineProvider<S, P, *>
 ) : Fragment(), VisualNavigator, Configurable<S, P> {
 
     interface Listener : VisualNavigator.Listener {
@@ -107,7 +107,7 @@ class PdfNavigatorFragment<S : Configurable.Settings, P : Configurable.Preferenc
         viewModel.submitPreferences(preferences)
     }
 
-    private val viewModel: PdfNavigatorViewModel<S, P, E> by viewModels {
+    private val viewModel: PdfNavigatorViewModel<S, P> by viewModels {
         PdfNavigatorViewModel.createFactory(
             requireActivity().application,
             publication,
diff --git a/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorViewModel.kt b/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorViewModel.kt
index 220458dfca..e67c11608e 100644
--- a/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorViewModel.kt
+++ b/readium/navigator/src/main/java/org/readium/r2/navigator/pdf/PdfNavigatorViewModel.kt
@@ -22,12 +22,12 @@ import org.readium.r2.shared.publication.Publication
 import org.readium.r2.shared.publication.services.positions
 
 @OptIn(ExperimentalReadiumApi::class)
-internal class PdfNavigatorViewModel<S : Configurable.Settings, P : Configurable.Preferences<P>, E : PreferencesEditor<P>>(
+internal class PdfNavigatorViewModel<S : Configurable.Settings, P : Configurable.Preferences<P>>(
     application: Application,
     private val publication: Publication,
     initialLocator: Locator,
     initialPreferences: P,
-    private val pdfEngineProvider: PdfEngineProvider<S, P, E>
+    private val pdfEngineProvider: PdfEngineProvider<S, P, *>
 ) : AndroidViewModel(application) {
 
     private val _currentLocator: MutableStateFlow<Locator> =
diff --git a/test-app/src/main/java/org/readium/r2/testapp/reader/PdfReaderFragment.kt b/test-app/src/main/java/org/readium/r2/testapp/reader/PdfReaderFragment.kt
index 01dcbb062a..f668588454 100644
--- a/test-app/src/main/java/org/readium/r2/testapp/reader/PdfReaderFragment.kt
+++ b/test-app/src/main/java/org/readium/r2/testapp/reader/PdfReaderFragment.kt
@@ -13,7 +13,6 @@ import android.view.ViewGroup
 import android.widget.Toast
 import androidx.fragment.app.commitNow
 import org.readium.adapters.pdfium.navigator.PdfiumPreferences
-import org.readium.adapters.pdfium.navigator.PdfiumPreferencesEditor
 import org.readium.adapters.pdfium.navigator.PdfiumSettings
 import org.readium.r2.navigator.pdf.PdfNavigatorFragment
 import org.readium.r2.shared.ExperimentalReadiumApi
@@ -25,7 +24,7 @@ import org.readium.r2.testapp.reader.preferences.UserPreferencesViewModel
 @OptIn(ExperimentalReadiumApi::class)
 class PdfReaderFragment : VisualReaderFragment(), PdfNavigatorFragment.Listener {
 
-    override lateinit var navigator: PdfNavigatorFragment<PdfiumSettings, PdfiumPreferences, PdfiumPreferencesEditor>
+    override lateinit var navigator: PdfNavigatorFragment<PdfiumSettings, PdfiumPreferences>
 
     override fun onCreate(savedInstanceState: Bundle?) {
         val readerData = model.readerInitData as PdfReaderInitData
@@ -51,9 +50,9 @@ class PdfReaderFragment : VisualReaderFragment(), PdfNavigatorFragment.Listener
                 replace(R.id.fragment_reader_container, PdfNavigatorFragment::class.java, Bundle(), NAVIGATOR_FRAGMENT_TAG)
             }
         }
-        navigator = childFragmentManager.findFragmentByTag(NAVIGATOR_FRAGMENT_TAG)!!
-            as PdfNavigatorFragment<PdfiumSettings, PdfiumPreferences, PdfiumPreferencesEditor>
         @Suppress("Unchecked_cast")
+        navigator = childFragmentManager.findFragmentByTag(NAVIGATOR_FRAGMENT_TAG)!!
+            as PdfNavigatorFragment<PdfiumSettings, PdfiumPreferences>
         return view
     }