diff --git a/app/src/main/java/org/schabi/newpipe/player/Player.java b/app/src/main/java/org/schabi/newpipe/player/Player.java
index 4d1accf26..111a98551 100644
--- a/app/src/main/java/org/schabi/newpipe/player/Player.java
+++ b/app/src/main/java/org/schabi/newpipe/player/Player.java
@@ -492,15 +492,15 @@ public final class Player implements PlaybackListener, Listener {
 
         switch (playerType) {
             case MAIN:
-                UIs.destroyAll(PopupPlayerUi.class);
+                UIs.destroyAllOfType(PopupPlayerUi.class);
                 UIs.addAndPrepare(new MainPlayerUi(this, binding));
                 break;
             case POPUP:
-                UIs.destroyAll(MainPlayerUi.class);
+                UIs.destroyAllOfType(MainPlayerUi.class);
                 UIs.addAndPrepare(new PopupPlayerUi(this, binding));
                 break;
             case AUDIO:
-                UIs.destroyAll(VideoPlayerUi.class);
+                UIs.destroyAllOfType(VideoPlayerUi.class);
                 break;
         }
     }
@@ -606,7 +606,7 @@ public final class Player implements PlaybackListener, Listener {
         databaseUpdateDisposable.clear();
         progressUpdateDisposable.set(null);
 
-        UIs.destroyAll(Object.class); // destroy every UI: obviously every UI extends Object
+        UIs.destroyAllOfType(null);
     }
 
     public void setRecovery() {
@@ -1995,6 +1995,10 @@ public final class Player implements PlaybackListener, Listener {
         triggerProgressUpdate();
     }
 
+    /**
+     * Remove the listener, if it was set.
+     * @param listener listener to remove
+     * */
     public void removeFragmentListener(final PlayerServiceEventListener listener) {
         if (fragmentListener == listener) {
             fragmentListener = null;
@@ -2009,6 +2013,10 @@ public final class Player implements PlaybackListener, Listener {
         triggerProgressUpdate();
     }
 
+    /**
+     * Remove the listener, if it was set.
+     * @param listener listener to remove
+     * */
     void removeActivityListener(final PlayerEventListener listener) {
         if (activityListener == listener) {
             activityListener = null;
diff --git a/app/src/main/java/org/schabi/newpipe/player/ui/PlayerUiList.kt b/app/src/main/java/org/schabi/newpipe/player/ui/PlayerUiList.kt
index e258d5ac1..24a46d1ef 100644
--- a/app/src/main/java/org/schabi/newpipe/player/ui/PlayerUiList.kt
+++ b/app/src/main/java/org/schabi/newpipe/player/ui/PlayerUiList.kt
@@ -50,19 +50,19 @@ class PlayerUiList(vararg initialPlayerUis: PlayerUi) {
 
     /**
      * Destroys all matching player UIs and removes them from the list.
-     * @param playerUiType the class of the player UI to destroy;
-     * the [Class.isInstance] method will be used, so even subclasses will be
+     * @param playerUiType the class of the player UI to destroy, everything if `null`.
+     * The [Class.isInstance] method will be used, so even subclasses will be
      * destroyed and removed
      * @param T the class type parameter </T>
      * */
-    fun <T> destroyAll(playerUiType: Class<T?>) {
+    fun <T : PlayerUi> destroyAllOfType(playerUiType: Class<T>? = null) {
         val toDestroy = mutableListOf<PlayerUi>()
 
         // short blocking removal from class to prevent interfering from other threads
         playerUis.runWithLockSync {
             val new = mutableListOf<PlayerUi>()
             for (ui in lockData) {
-                if (playerUiType.isInstance(ui)) {
+                if (playerUiType == null || playerUiType.isInstance(ui)) {
                     toDestroy.add(ui)
                 } else {
                     new.add(ui)
@@ -83,7 +83,7 @@ class PlayerUiList(vararg initialPlayerUis: PlayerUi) {
      * @param T the class type parameter
      * @return the first player UI of the required type found in the list, or null
      </T> */
-    fun <T> get(playerUiType: Class<T>): T? =
+    fun <T : PlayerUi> get(playerUiType: Class<T>): T? =
         playerUis.runWithLockSync {
             for (ui in lockData) {
                 if (playerUiType.isInstance(ui)) {
@@ -105,7 +105,7 @@ class PlayerUiList(vararg initialPlayerUis: PlayerUi) {
      * [Optional] otherwise
      </T> */
     @Deprecated("use get", ReplaceWith("get(playerUiType)"))
-    fun <T> getOpt(playerUiType: Class<T>): Optional<T & Any> =
+    fun <T : PlayerUi> getOpt(playerUiType: Class<T>): Optional<T> =
         Optional.ofNullable(get(playerUiType))
 
     /**