diff --git a/demos/session/src/main/java/androidx/media3/demo/session/PlayableFolderActivity.kt b/demos/session/src/main/java/androidx/media3/demo/session/PlayableFolderActivity.kt
index e4a048ae91..97cf2b8110 100644
--- a/demos/session/src/main/java/androidx/media3/demo/session/PlayableFolderActivity.kt
+++ b/demos/session/src/main/java/androidx/media3/demo/session/PlayableFolderActivity.kt
@@ -88,7 +88,7 @@ class PlayableFolderActivity : AppCompatActivity() {
       browser.shuffleModeEnabled = true
       browser.prepare()
       browser.play()
-      browser?.sessionActivity?.send()
+      browser.sessionActivity?.send()
     }
 
     findViewById<Button>(R.id.play_button).setOnClickListener {
diff --git a/demos/session_service/src/main/java/androidx/media3/demo/session/DemoMediaLibrarySessionCallback.kt b/demos/session_service/src/main/java/androidx/media3/demo/session/DemoMediaLibrarySessionCallback.kt
index c6e5f4247a..362ea7affc 100644
--- a/demos/session_service/src/main/java/androidx/media3/demo/session/DemoMediaLibrarySessionCallback.kt
+++ b/demos/session_service/src/main/java/androidx/media3/demo/session/DemoMediaLibrarySessionCallback.kt
@@ -25,6 +25,7 @@ import androidx.media3.session.CommandButton
 import androidx.media3.session.LibraryResult
 import androidx.media3.session.MediaLibraryService
 import androidx.media3.session.MediaSession
+import androidx.media3.session.MediaSession.MediaItemsWithStartPosition
 import androidx.media3.session.SessionCommand
 import androidx.media3.session.SessionResult
 import com.google.common.collect.ImmutableList
@@ -32,7 +33,7 @@ import com.google.common.util.concurrent.Futures
 import com.google.common.util.concurrent.ListenableFuture
 
 /** A [MediaLibraryService.MediaLibrarySession.Callback] implementation. */
-open class DemoMediaLibrarySessionCallback(private val context: Context) :
+open class DemoMediaLibrarySessionCallback(context: Context) :
   MediaLibraryService.MediaLibrarySession.Callback {
 
   init {
@@ -155,14 +156,7 @@ open class DemoMediaLibrarySessionCallback(private val context: Context) :
     controller: MediaSession.ControllerInfo,
     mediaItems: List<MediaItem>
   ): ListenableFuture<List<MediaItem>> {
-    val playlist = mutableListOf<MediaItem>()
-    mediaItems.forEach { mediaItem ->
-      when (mediaItem.requestMetadata.searchQuery) {
-        null -> MediaItemTree.getItem(mediaItem.mediaId)?.let { playlist.add(it) }
-        else -> playlist.addAll(MediaItemTree.search(mediaItem.requestMetadata.searchQuery!!))
-      }
-    }
-    return Futures.immediateFuture(playlist)
+    return Futures.immediateFuture(resolveMediaItems(mediaItems))
   }
 
   @OptIn(UnstableApi::class) // MediaSession.MediaItemsWithStartPosition
@@ -172,34 +166,57 @@ open class DemoMediaLibrarySessionCallback(private val context: Context) :
     mediaItems: List<MediaItem>,
     startIndex: Int,
     startPositionMs: Long
-  ): ListenableFuture<MediaSession.MediaItemsWithStartPosition> {
+  ): ListenableFuture<MediaItemsWithStartPosition> {
     if (mediaItems.size == 1) {
       // Try to expand a single item to a playlist.
-      val mediaId = mediaItems.first().mediaId
-      val mediaItem = MediaItemTree.getItem(mediaId)
-      val playlist = mutableListOf<MediaItem>()
-      var indexInPlaylist = startIndex
-      mediaItem?.apply {
-        if (mediaMetadata.isBrowsable == true) {
-          // Get children browsable item.
-          playlist.addAll(MediaItemTree.getChildren(mediaId))
-        } else if (requestMetadata.searchQuery == null) {
-          // Try to get the parent and its children.
-          MediaItemTree.getParentId(mediaId)?.let {
-            playlist.addAll(MediaItemTree.getChildren(it))
-            indexInPlaylist = MediaItemTree.getIndexInMediaItems(mediaId, playlist)
-          }
-        }
-      }
-      if (playlist.isNotEmpty()) {
-        // Return the expanded playlist to be set on the player of the session.
-        return Futures.immediateFuture(
-          MediaSession.MediaItemsWithStartPosition(playlist, indexInPlaylist, startPositionMs)
-        )
+      maybeExpandSingleItemToPlaylist(mediaItems.first(), startIndex, startPositionMs)?.also {
+        return Futures.immediateFuture(it)
       }
     }
-    // Let super serve the request if item isn't expanded.
-    return super.onSetMediaItems(mediaSession, browser, mediaItems, startIndex, startPositionMs)
+    return Futures.immediateFuture(
+      MediaItemsWithStartPosition(resolveMediaItems(mediaItems), startIndex, startPositionMs)
+    )
+  }
+
+  private fun resolveMediaItems(mediaItems: List<MediaItem>): List<MediaItem> {
+    val playlist = mutableListOf<MediaItem>()
+    mediaItems.forEach { mediaItem ->
+      if (mediaItem.mediaId.isNotEmpty()) {
+        MediaItemTree.expandItem(mediaItem)?.let { playlist.add(it) }
+      } else if (mediaItem.requestMetadata.searchQuery != null) {
+        playlist.addAll(MediaItemTree.search(mediaItem.requestMetadata.searchQuery!!))
+      }
+    }
+    return playlist
+  }
+
+  @OptIn(UnstableApi::class) // MediaSession.MediaItemsWithStartPosition
+  private fun maybeExpandSingleItemToPlaylist(
+    mediaItem: MediaItem,
+    startIndex: Int,
+    startPositionMs: Long
+  ): MediaItemsWithStartPosition? {
+    var playlist = listOf<MediaItem>()
+    var indexInPlaylist = startIndex
+    MediaItemTree.getItem(mediaItem.mediaId)?.apply {
+      if (mediaMetadata.isBrowsable == true) {
+        // Get children browsable item.
+        playlist = MediaItemTree.getChildren(mediaId)
+      } else if (requestMetadata.searchQuery == null) {
+        // Try to get the parent and its children.
+        MediaItemTree.getParentId(mediaId)?.let {
+          playlist =
+            MediaItemTree.getChildren(it).map { mediaItem ->
+              if (mediaItem.mediaId == mediaId) MediaItemTree.expandItem(mediaItem)!! else mediaItem
+            }
+          indexInPlaylist = MediaItemTree.getIndexInMediaItems(mediaId, playlist)
+        }
+      }
+    }
+    if (playlist.isNotEmpty()) {
+      return MediaItemsWithStartPosition(playlist, indexInPlaylist, startPositionMs)
+    }
+    return null
   }
 
   override fun onSearch(
diff --git a/demos/session_service/src/main/java/androidx/media3/demo/session/MediaItemTree.kt b/demos/session_service/src/main/java/androidx/media3/demo/session/MediaItemTree.kt
index 5211757319..6951375e9f 100644
--- a/demos/session_service/src/main/java/androidx/media3/demo/session/MediaItemTree.kt
+++ b/demos/session_service/src/main/java/androidx/media3/demo/session/MediaItemTree.kt
@@ -17,9 +17,11 @@ package androidx.media3.demo.session
 
 import android.content.res.AssetManager
 import android.net.Uri
+import androidx.annotation.OptIn
 import androidx.media3.common.MediaItem
 import androidx.media3.common.MediaItem.SubtitleConfiguration
 import androidx.media3.common.MediaMetadata
+import androidx.media3.common.util.UnstableApi
 import com.google.common.collect.ImmutableList
 import java.io.BufferedReader
 import java.lang.StringBuilder
@@ -275,6 +277,18 @@ object MediaItemTree {
     return treeNodes[id]?.item
   }
 
+  fun expandItem(item: MediaItem): MediaItem? {
+    val treeItem = getItem(item.mediaId) ?: return null
+    @OptIn(UnstableApi::class) // MediaMetadata.populate
+    val metadata = treeItem.mediaMetadata.buildUpon().populate(item.mediaMetadata).build()
+    return item
+      .buildUpon()
+      .setMediaMetadata(metadata)
+      .setSubtitleConfigurations(treeItem.localConfiguration?.subtitleConfigurations ?: listOf())
+      .setUri(treeItem.localConfiguration?.uri)
+      .build()
+  }
+
   /**
    * Returns the media ID of the parent of the given media ID, or null if the media ID wasn't found.
    *
@@ -342,19 +356,6 @@ object MediaItemTree {
     return treeNodes[id]?.getChildren() ?: listOf()
   }
 
-  fun getRandomItem(): MediaItem {
-    var curRoot = getRootItem()
-    while (curRoot.mediaMetadata.isBrowsable == true) {
-      val children = getChildren(curRoot.mediaId)
-      curRoot = children.random()
-    }
-    return curRoot
-  }
-
-  fun getItemFromTitle(title: String): MediaItem? {
-    return titleMap[title]?.item
-  }
-
   private fun normalizeSearchText(text: CharSequence?): String {
     if (text.isNullOrEmpty() || text.trim().length == 1) {
       return ""