Add "New collection..." item to dropdown

osu.Game.Tests/Visual/SongSelect/TestSceneFilterControl.cs

@@ -184,6 +184,29 @@ namespace osu.Game.Tests.Visual.SongSelect
             AddAssert("button is plus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.PlusSquare));
         }
 
+        [Test]
+        public void TestNewCollectionFilterIsNotSelected()
+        {
+            addExpandHeaderStep();
+
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddStep("select collection", () =>
+            {
+                InputManager.MoveMouseTo(getCollectionDropdownItems().ElementAt(1));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            addExpandHeaderStep();
+
+            AddStep("click manage collections filter", () =>
+            {
+                InputManager.MoveMouseTo(getCollectionDropdownItems().Last());
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("collection filter still selected", () => control.CreateCriteria().Collection?.CollectionName.Value == "1");
+        }
+
         private void assertCollectionHeaderDisplays(string collectionName, bool shouldDisplay = true)
             => AddAssert($"collection dropdown header displays '{collectionName}'",
                 () => shouldDisplay == (control.ChildrenOfType<CollectionFilterDropdown.CollectionDropdownHeader>().Single().ChildrenOfType<SpriteText>().First().Text == collectionName));

osu.Game/Screens/Select/CollectionFilter.cs

@@ -45,4 +45,21 @@ namespace osu.Game.Screens.Select
         public virtual bool ContainsBeatmap(BeatmapInfo beatmap)
             => Collection?.Beatmaps.Any(b => b.Equals(beatmap)) ?? true;
     }
+
+    public class AllBeatmapCollectionFilter : CollectionFilter
+    {
+        public AllBeatmapCollectionFilter()
+            : base(null)
+        {
+        }
+    }
+
+    public class NewCollectionFilter : CollectionFilter
+    {
+        public NewCollectionFilter()
+            : base(null)
+        {
+            CollectionName.Value = "New collection...";
+        }
+    }
 }

osu.Game/Screens/Select/CollectionFilterDropdown.cs

@@ -29,6 +29,9 @@ namespace osu.Game.Screens.Select
         private readonly IBindableList<BeatmapInfo> beatmaps = new BindableList<BeatmapInfo>();
         private readonly BindableList<CollectionFilter> filters = new BindableList<CollectionFilter>();
 
+        [Resolved(CanBeNull = true)]
+        private ManageCollectionsDialog manageCollectionsDialog { get; set; }
+
         public CollectionFilterDropdown()
         {
             ItemSource = filters;
@@ -57,10 +60,11 @@ namespace osu.Game.Screens.Select
             var selectedItem = SelectedItem?.Value?.Collection;
 
             filters.Clear();
-            filters.Add(new CollectionFilter(null));
+            filters.Add(new AllBeatmapCollectionFilter());
             filters.AddRange(collections.Select(c => new CollectionFilter(c)));
+            filters.Add(new NewCollectionFilter());
 
-            Current.Value = filters.SingleOrDefault(f => f.Collection == selectedItem) ?? filters[0];
+            Current.Value = filters.SingleOrDefault(f => f.Collection != null && f.Collection == selectedItem) ?? filters[0];
         }
 
         /// <summary>
@@ -78,6 +82,14 @@ namespace osu.Game.Screens.Select
                 beatmaps.BindTo(filter.NewValue.Collection.Beatmaps);
 
             beatmaps.CollectionChanged += filterBeatmapsChanged;
+
+            // Never select the manage collection filter - rollback to the previous filter.
+            // This is done after the above since it is important that bindable is unbound from OldValue, which is lost after forcing it back to the old value.
+            if (filter.NewValue is NewCollectionFilter)
+            {
+                Current.Value = filter.OldValue;
+                manageCollectionsDialog?.Show();
+            }
         }
 
         /// <summary>
@@ -90,7 +102,7 @@ namespace osu.Game.Screens.Select
             Current.TriggerChange();
         }
 
-        protected override string GenerateItemText(CollectionFilter item) => item.Collection?.Name.Value ?? "All beatmaps";
+        protected override string GenerateItemText(CollectionFilter item) => item.CollectionName.Value;
 
         protected override DropdownHeader CreateHeader() => new CollectionDropdownHeader
         {