Merge branch 'master' into dialog-overlay-thread-woes

osu.Game.Rulesets.Catch/Edit/CatchHitObjectComposer.cs

@@ -89,9 +89,9 @@ namespace osu.Game.Rulesets.Catch.Edit
             new TernaryButton(distanceSnapToggle, "Distance Snap", () => new SpriteIcon { Icon = FontAwesome.Solid.Ruler })
         });
 
-        public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition)
         {
-            var result = base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
+            var result = base.FindSnappedPositionAndTime(screenSpacePosition);
             result.ScreenSpacePosition.X = screenSpacePosition.X;
 
             if (distanceSnapGrid.IsPresent && distanceSnapGrid.GetSnappedPosition(result.ScreenSpacePosition) is SnapResult snapResult &&

osu.Game.Rulesets.Mania.Tests/Editor/TestSceneManiaBeatSnapGrid.cs

@@ -97,12 +97,12 @@ namespace osu.Game.Rulesets.Mania.Tests.Editor
             set => InternalChild = value;
         }
 
-        public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition)
         {
             throw new System.NotImplementedException();
         }
 
-        public override SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPosition(Vector2 screenSpacePosition)
         {
             throw new System.NotImplementedException();
         }

osu.Game.Rulesets.Mania/Edit/ManiaHitObjectComposer.cs

@@ -56,9 +56,9 @@ namespace osu.Game.Rulesets.Mania.Edit
         protected override Playfield PlayfieldAtScreenSpacePosition(Vector2 screenSpacePosition) =>
             Playfield.GetColumnByPosition(screenSpacePosition);
 
-        public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition)
         {
-            var result = base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
+            var result = base.FindSnappedPositionAndTime(screenSpacePosition);
 
             switch (ScrollingInfo.Direction.Value)
             {
@@ -112,7 +112,7 @@ namespace osu.Game.Rulesets.Mania.Edit
             }
             else
             {
-                var result = SnapScreenSpacePositionToValidTime(inputManager.CurrentState.Mouse.Position);
+                var result = FindSnappedPositionAndTime(inputManager.CurrentState.Mouse.Position);
                 if (result.Time is double time)
                     beatSnapGrid.SelectionTimeRange = (time, time);
                 else

osu.Game.Rulesets.Osu.Tests/Editor/TestSceneOsuDistanceSnapGrid.cs

@@ -182,10 +182,10 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
 
         private class SnapProvider : IDistanceSnapProvider
         {
-            public SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition) =>
+            public SnapResult FindSnappedPosition(Vector2 screenSpacePosition) =>
                 new SnapResult(screenSpacePosition, null);
 
-            public SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition) => new SnapResult(screenSpacePosition, 0);
+            public SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition) => new SnapResult(screenSpacePosition, 0);
 
             public IBindable<double> DistanceSpacingMultiplier { get; } = new BindableDouble(1);
 
@@ -195,9 +195,9 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
 
             public double DistanceToDuration(HitObject referenceObject, float distance) => distance;
 
-            public double GetSnappedDurationFromDistance(HitObject referenceObject, float distance) => 0;
+            public double FindSnappedDuration(HitObject referenceObject, float distance) => 0;
 
-            public float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance) => 0;
+            public float FindSnappedDistance(HitObject referenceObject, float distance) => 0;
         }
     }
 }

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/Components/PathControlPointVisualiser.cs

@@ -255,7 +255,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
             {
                 // Special handling for selections containing head control point - the position of the slider changes which means the snapped position and time have to be taken into account
                 Vector2 newHeadPosition = Parent.ToScreenSpace(e.MousePosition + (dragStartPositions[0] - dragStartPositions[draggedControlPointIndex]));
-                var result = snapProvider?.SnapScreenSpacePositionToValidTime(newHeadPosition);
+                var result = snapProvider?.FindSnappedPositionAndTime(newHeadPosition);
 
                 Vector2 movementDelta = Parent.ToLocalSpace(result?.ScreenSpacePosition ?? newHeadPosition) - slider.Position;
 

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs

@@ -220,7 +220,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
 
         private void updateSlider()
         {
-            HitObject.Path.ExpectedDistance.Value = snapProvider?.GetSnappedDistanceFromDistance(HitObject, (float)HitObject.Path.CalculatedDistance) ?? (float)HitObject.Path.CalculatedDistance;
+            HitObject.Path.ExpectedDistance.Value = snapProvider?.FindSnappedDistance(HitObject, (float)HitObject.Path.CalculatedDistance) ?? (float)HitObject.Path.CalculatedDistance;
 
             bodyPiece.UpdateFrom(HitObject);
             headCirclePiece.UpdateFrom(HitObject.HeadCircle);

osu.Game.Rulesets.Osu/Edit/OsuHitObjectComposer.cs

@@ -123,7 +123,7 @@ namespace osu.Game.Rulesets.Osu.Edit
             }
         }
 
-        public override SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPosition(Vector2 screenSpacePosition)
         {
             if (snapToVisibleBlueprints(screenSpacePosition, out var snapResult))
                 return snapResult;
@@ -131,9 +131,9 @@ namespace osu.Game.Rulesets.Osu.Edit
             return new SnapResult(screenSpacePosition, null);
         }
 
-        public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition)
         {
-            var positionSnap = SnapScreenSpacePositionToValidPosition(screenSpacePosition);
+            var positionSnap = FindSnappedPosition(screenSpacePosition);
             if (positionSnap.ScreenSpacePosition != screenSpacePosition)
                 return positionSnap;
 
@@ -149,7 +149,7 @@ namespace osu.Game.Rulesets.Osu.Edit
                 return new SnapResult(rectangularPositionSnapGrid.ToScreenSpace(pos), null, PlayfieldAtScreenSpacePosition(screenSpacePosition));
             }
 
-            return base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
+            return base.FindSnappedPositionAndTime(screenSpacePosition);
         }
 
         private bool snapToVisibleBlueprints(Vector2 screenSpacePosition, out SnapResult snapResult)

osu.Game.Rulesets.Osu/Mods/OsuModAlternate.cs

@@ -25,7 +25,7 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override string Acronym => @"AL";
         public override string Description => @"Don't use the same key twice in a row!";
         public override double ScoreMultiplier => 1.0;
-        public override Type[] IncompatibleMods => new[] { typeof(ModAutoplay) };
+        public override Type[] IncompatibleMods => new[] { typeof(ModAutoplay), typeof(ModRelax) };
         public override ModType Type => ModType.Conversion;
         public override IconUsage? Icon => FontAwesome.Solid.Keyboard;
 

osu.Game.Rulesets.Osu/Mods/OsuModAutoplay.cs

@@ -12,7 +12,7 @@ namespace osu.Game.Rulesets.Osu.Mods
 {
     public class OsuModAutoplay : ModAutoplay
     {
-        public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModMagnetised), typeof(OsuModAutopilot), typeof(OsuModSpunOut) }).ToArray();
+        public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModMagnetised), typeof(OsuModAutopilot), typeof(OsuModSpunOut), typeof(OsuModAlternate) }).ToArray();
 
         public override ModReplayData CreateReplayData(IBeatmap beatmap, IReadOnlyList<Mod> mods)
             => new ModReplayData(new OsuAutoGenerator(beatmap, mods).Generate(), new ModCreatedUser { Username = "Autoplay" });

osu.Game.Rulesets.Osu/Mods/OsuModCinema.cs

@@ -13,7 +13,7 @@ namespace osu.Game.Rulesets.Osu.Mods
 {
     public class OsuModCinema : ModCinema<OsuHitObject>
     {
-        public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModMagnetised), typeof(OsuModAutopilot), typeof(OsuModSpunOut) }).ToArray();
+        public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModMagnetised), typeof(OsuModAutopilot), typeof(OsuModSpunOut), typeof(OsuModAlternate) }).ToArray();
 
         public override ModReplayData CreateReplayData(IBeatmap beatmap, IReadOnlyList<Mod> mods)
             => new ModReplayData(new OsuAutoGenerator(beatmap, mods).Generate(), new ModCreatedUser { Username = "Autoplay" });

osu.Game.Rulesets.Osu/Mods/OsuModRelax.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Rulesets.Osu.Mods
     public class OsuModRelax : ModRelax, IUpdatableByPlayfield, IApplicableToDrawableRuleset<OsuHitObject>, IApplicableToPlayer
     {
         public override string Description => @"You don't need to click. Give your clicking/tapping fingers a break from the heat of things.";
-        public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModAutopilot), typeof(OsuModMagnetised) }).ToArray();
+        public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModAutopilot), typeof(OsuModMagnetised), typeof(OsuModAlternate) }).ToArray();
 
         /// <summary>
         /// How early before a hitobject's start time to trigger a hit.

osu.Game.Rulesets.Osu/Mods/OsuModStrictTracking.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Linq;
 using System.Threading;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Mods;
@@ -23,9 +22,8 @@ namespace osu.Game.Rulesets.Osu.Mods
     {
         public override string Name => @"Strict Tracking";
         public override string Acronym => @"ST";
-        public override IconUsage? Icon => FontAwesome.Solid.PenFancy;
         public override ModType Type => ModType.DifficultyIncrease;
-        public override string Description => @"Follow circles just got serious...";
+        public override string Description => @"Once you start a slider, follow precisely or get a miss.";
         public override double ScoreMultiplier => 1.0;
         public override Type[] IncompatibleMods => new[] { typeof(ModClassic), typeof(OsuModTarget) };
 

osu.Game.Tests/Editing/TestSceneHitObjectComposerDistanceSnapping.cs

@@ -213,10 +213,10 @@ namespace osu.Game.Tests.Editing
             => AddAssert($"distance = {distance} -> duration = {expectedDuration}", () => composer.DistanceToDuration(new HitObject(), distance) == expectedDuration);
 
         private void assertSnappedDuration(float distance, double expectedDuration)
-            => AddAssert($"distance = {distance} -> duration = {expectedDuration} (snapped)", () => composer.GetSnappedDurationFromDistance(new HitObject(), distance) == expectedDuration);
+            => AddAssert($"distance = {distance} -> duration = {expectedDuration} (snapped)", () => composer.FindSnappedDuration(new HitObject(), distance) == expectedDuration);
 
         private void assertSnappedDistance(float distance, float expectedDistance)
-            => AddAssert($"distance = {distance} -> distance = {expectedDistance} (snapped)", () => composer.GetSnappedDistanceFromDistance(new HitObject(), distance) == expectedDistance);
+            => AddAssert($"distance = {distance} -> distance = {expectedDistance} (snapped)", () => composer.FindSnappedDistance(new HitObject(), distance) == expectedDistance);
 
         private class TestHitObjectComposer : OsuHitObjectComposer
         {

osu.Game.Tests/Visual/Editing/TestSceneDistanceSnapGrid.cs

@@ -162,10 +162,10 @@ namespace osu.Game.Tests.Visual.Editing
 
         private class SnapProvider : IDistanceSnapProvider
         {
-            public SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition) =>
+            public SnapResult FindSnappedPosition(Vector2 screenSpacePosition) =>
                 new SnapResult(screenSpacePosition, null);
 
-            public SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition) => new SnapResult(screenSpacePosition, 0);
+            public SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition) => new SnapResult(screenSpacePosition, 0);
 
             public IBindable<double> DistanceSpacingMultiplier { get; } = new BindableDouble(1);
 
@@ -175,9 +175,9 @@ namespace osu.Game.Tests.Visual.Editing
 
             public double DistanceToDuration(HitObject referenceObject, float distance) => distance;
 
-            public double GetSnappedDurationFromDistance(HitObject referenceObject, float distance) => 0;
+            public double FindSnappedDuration(HitObject referenceObject, float distance) => 0;
 
-            public float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance) => 0;
+            public float FindSnappedDistance(HitObject referenceObject, float distance) => 0;
         }
     }
 }

osu.Game.Tests/Visual/Editing/TestSceneHitObjectComposer.cs

@@ -19,6 +19,7 @@ using osu.Game.Rulesets.Osu.Edit;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Screens.Edit;
 using osu.Game.Screens.Edit.Components.RadioButtons;
+using osu.Game.Screens.Edit.Components.TernaryButtons;
 using osu.Game.Screens.Edit.Compose.Components;
 using osuTK;
 using osuTK.Input;
@@ -70,6 +71,11 @@ namespace osu.Game.Tests.Visual.Editing
                 Child = editorBeatmapContainer = new EditorBeatmapContainer(Beatmap.Value)
                 {
                     Child = hitObjectComposer = new OsuHitObjectComposer(new OsuRuleset())
+                    {
+                        // force the composer to fully overlap the playfield area by setting a 4:3 aspect ratio.
+                        FillMode = FillMode.Fit,
+                        FillAspectRatio = 4 / 3f
+                    }
                 };
             });
         }
@@ -87,6 +93,65 @@ namespace osu.Game.Tests.Visual.Editing
             AddAssert("Tool changed", () => hitObjectComposer.ChildrenOfType<ComposeBlueprintContainer>().First().CurrentTool is HitCircleCompositionTool);
         }
 
+        [Test]
+        public void TestPlacementFailsWhenClickingButton()
+        {
+            AddStep("clear all control points and hitobjects", () =>
+            {
+                editorBeatmap.ControlPointInfo.Clear();
+                editorBeatmap.Clear();
+            });
+
+            AddStep("Add timing point", () => editorBeatmap.ControlPointInfo.Add(0, new TimingControlPoint()));
+
+            AddStep("Change to hitcircle", () => hitObjectComposer.ChildrenOfType<EditorRadioButton>().First(d => d.Button.Label == "HitCircle").TriggerClick());
+
+            AddStep("move mouse to overlapping toggle button", () =>
+            {
+                var playfield = hitObjectComposer.Playfield.ScreenSpaceDrawQuad;
+                var button = hitObjectComposer
+                             .ChildrenOfType<ExpandingToolboxContainer>().First()
+                             .ChildrenOfType<DrawableTernaryButton>().First(b => playfield.Contains(b.ScreenSpaceDrawQuad.Centre));
+
+                InputManager.MoveMouseTo(button);
+            });
+
+            AddAssert("no circles placed", () => editorBeatmap.HitObjects.Count == 0);
+
+            AddStep("attempt place circle", () => InputManager.Click(MouseButton.Left));
+
+            AddAssert("no circles placed", () => editorBeatmap.HitObjects.Count == 0);
+        }
+
+        [Test]
+        public void TestPlacementWithinToolboxScrollArea()
+        {
+            AddStep("clear all control points and hitobjects", () =>
+            {
+                editorBeatmap.ControlPointInfo.Clear();
+                editorBeatmap.Clear();
+            });
+
+            AddStep("Add timing point", () => editorBeatmap.ControlPointInfo.Add(0, new TimingControlPoint()));
+
+            AddStep("Change to hitcircle", () => hitObjectComposer.ChildrenOfType<EditorRadioButton>().First(d => d.Button.Label == "HitCircle").TriggerClick());
+
+            AddStep("move mouse to scroll area", () =>
+            {
+                // Specifically wanting to test the area of overlap between the left expanding toolbox container
+                // and the playfield/composer.
+                var scrollArea = hitObjectComposer.ChildrenOfType<ExpandingToolboxContainer>().First().ScreenSpaceDrawQuad;
+                var playfield = hitObjectComposer.Playfield.ScreenSpaceDrawQuad;
+                InputManager.MoveMouseTo(new Vector2(scrollArea.TopLeft.X + 1, playfield.Centre.Y));
+            });
+
+            AddAssert("no circles placed", () => editorBeatmap.HitObjects.Count == 0);
+
+            AddStep("place circle", () => InputManager.Click(MouseButton.Left));
+
+            AddAssert("circle placed", () => editorBeatmap.HitObjects.Count == 1);
+        }
+
         [Test]
         public void TestDistanceSpacingHotkeys()
         {

osu.Game.Tests/Visual/UserInterface/TestSceneModSelectScreen.cs

@@ -2,17 +2,21 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Testing;
 using osu.Framework.Utils;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Overlays.Mods;
+using osu.Game.Overlays.Settings;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Osu.Mods;
 using osuTK.Input;
 
@@ -64,6 +68,7 @@ namespace osu.Game.Tests.Visual.UserInterface
                 return Precision.AlmostEquals(multiplier, modSelectScreen.ChildrenOfType<DifficultyMultiplierDisplay>().Single().Current.Value);
             });
             assertCustomisationToggleState(disabled: false, active: false);
+            AddAssert("setting items created", () => modSelectScreen.ChildrenOfType<ISettingsItem>().Any());
         }
 
         [Test]
@@ -78,6 +83,7 @@ namespace osu.Game.Tests.Visual.UserInterface
                 return Precision.AlmostEquals(multiplier, modSelectScreen.ChildrenOfType<DifficultyMultiplierDisplay>().Single().Current.Value);
             });
             assertCustomisationToggleState(disabled: false, active: false);
+            AddAssert("setting items created", () => modSelectScreen.ChildrenOfType<ISettingsItem>().Any());
         }
 
         [Test]
@@ -98,17 +104,25 @@ namespace osu.Game.Tests.Visual.UserInterface
 
             AddStep("activate DT", () => getPanelForMod(typeof(OsuModDoubleTime)).TriggerClick());
             AddAssert("DT active", () => SelectedMods.Value.Single().GetType() == typeof(OsuModDoubleTime));
+            AddAssert("DT panel active", () => getPanelForMod(typeof(OsuModDoubleTime)).Active.Value);
 
             AddStep("activate NC", () => getPanelForMod(typeof(OsuModNightcore)).TriggerClick());
             AddAssert("only NC active", () => SelectedMods.Value.Single().GetType() == typeof(OsuModNightcore));
+            AddAssert("DT panel not active", () => !getPanelForMod(typeof(OsuModDoubleTime)).Active.Value);
+            AddAssert("NC panel active", () => getPanelForMod(typeof(OsuModNightcore)).Active.Value);
 
             AddStep("activate HR", () => getPanelForMod(typeof(OsuModHardRock)).TriggerClick());
             AddAssert("NC+HR active", () => SelectedMods.Value.Any(mod => mod.GetType() == typeof(OsuModNightcore))
                                             && SelectedMods.Value.Any(mod => mod.GetType() == typeof(OsuModHardRock)));
+            AddAssert("NC panel active", () => getPanelForMod(typeof(OsuModNightcore)).Active.Value);
+            AddAssert("HR panel active", () => getPanelForMod(typeof(OsuModHardRock)).Active.Value);
 
             AddStep("activate MR", () => getPanelForMod(typeof(OsuModMirror)).TriggerClick());
             AddAssert("NC+MR active", () => SelectedMods.Value.Any(mod => mod.GetType() == typeof(OsuModNightcore))
                                             && SelectedMods.Value.Any(mod => mod.GetType() == typeof(OsuModMirror)));
+            AddAssert("NC panel active", () => getPanelForMod(typeof(OsuModNightcore)).Active.Value);
+            AddAssert("HR panel not active", () => !getPanelForMod(typeof(OsuModHardRock)).Active.Value);
+            AddAssert("MR panel active", () => getPanelForMod(typeof(OsuModMirror)).Active.Value);
         }
 
         [Test]
@@ -169,6 +183,206 @@ namespace osu.Game.Tests.Visual.UserInterface
             assertCustomisationToggleState(disabled: true, active: false); // config was dismissed without explicit user action.
         }
 
+        /// <summary>
+        /// Ensure that two mod overlays are not cross polluting via central settings instances.
+        /// </summary>
+        [Test]
+        public void TestSettingsNotCrossPolluting()
+        {
+            Bindable<IReadOnlyList<Mod>> selectedMods2 = null;
+            ModSelectScreen modSelectScreen2 = null;
+
+            createScreen();
+            AddStep("select diff adjust", () => SelectedMods.Value = new Mod[] { new OsuModDifficultyAdjust() });
+
+            AddStep("set setting", () => modSelectScreen.ChildrenOfType<SettingsSlider<float>>().First().Current.Value = 8);
+
+            AddAssert("ensure setting is propagated", () => SelectedMods.Value.OfType<OsuModDifficultyAdjust>().Single().CircleSize.Value == 8);
+
+            AddStep("create second bindable", () => selectedMods2 = new Bindable<IReadOnlyList<Mod>>(new Mod[] { new OsuModDifficultyAdjust() }));
+
+            AddStep("create second overlay", () =>
+            {
+                Add(modSelectScreen2 = new UserModSelectScreen().With(d =>
+                {
+                    d.Origin = Anchor.TopCentre;
+                    d.Anchor = Anchor.TopCentre;
+                    d.SelectedMods.BindTarget = selectedMods2;
+                }));
+            });
+
+            AddStep("show", () => modSelectScreen2.Show());
+
+            AddAssert("ensure first is unchanged", () => SelectedMods.Value.OfType<OsuModDifficultyAdjust>().Single().CircleSize.Value == 8);
+            AddAssert("ensure second is default", () => selectedMods2.Value.OfType<OsuModDifficultyAdjust>().Single().CircleSize.Value == null);
+        }
+
+        [Test]
+        public void TestSettingsResetOnDeselection()
+        {
+            var osuModDoubleTime = new OsuModDoubleTime { SpeedChange = { Value = 1.2 } };
+
+            createScreen();
+            changeRuleset(0);
+
+            AddStep("set dt mod with custom rate", () => { SelectedMods.Value = new[] { osuModDoubleTime }; });
+
+            AddAssert("selected mod matches", () => (SelectedMods.Value.Single() as OsuModDoubleTime)?.SpeedChange.Value == 1.2);
+
+            AddStep("deselect", () => getPanelForMod(typeof(OsuModDoubleTime)).TriggerClick());
+            AddAssert("selected mods empty", () => SelectedMods.Value.Count == 0);
+
+            AddStep("reselect", () => getPanelForMod(typeof(OsuModDoubleTime)).TriggerClick());
+            AddAssert("selected mod has default value", () => (SelectedMods.Value.Single() as OsuModDoubleTime)?.SpeedChange.IsDefault == true);
+        }
+
+        [Test]
+        public void TestAnimationFlushOnClose()
+        {
+            createScreen();
+            changeRuleset(0);
+
+            AddStep("Select all fun mods", () =>
+            {
+                modSelectScreen.ChildrenOfType<ModColumn>()
+                               .Single(c => c.ModType == ModType.DifficultyIncrease)
+                               .SelectAll();
+            });
+
+            AddUntilStep("many mods selected", () => SelectedMods.Value.Count >= 5);
+
+            AddStep("trigger deselect and close overlay", () =>
+            {
+                modSelectScreen.ChildrenOfType<ModColumn>()
+                               .Single(c => c.ModType == ModType.DifficultyIncrease)
+                               .DeselectAll();
+
+                modSelectScreen.Hide();
+            });
+
+            AddAssert("all mods deselected", () => SelectedMods.Value.Count == 0);
+        }
+
+        [Test]
+        public void TestRulesetChanges()
+        {
+            createScreen();
+            changeRuleset(0);
+
+            var noFailMod = new OsuRuleset().GetModsFor(ModType.DifficultyReduction).FirstOrDefault(m => m is OsuModNoFail);
+
+            AddStep("set mods externally", () => { SelectedMods.Value = new[] { noFailMod }; });
+
+            changeRuleset(0);
+
+            AddAssert("ensure mods still selected", () => SelectedMods.Value.SingleOrDefault(m => m is OsuModNoFail) != null);
+
+            changeRuleset(3);
+
+            AddAssert("ensure mods not selected", () => SelectedMods.Value.Count == 0);
+
+            changeRuleset(0);
+
+            AddAssert("ensure mods not selected", () => SelectedMods.Value.Count == 0);
+        }
+
+        [Test]
+        public void TestExternallySetCustomizedMod()
+        {
+            createScreen();
+            changeRuleset(0);
+
+            AddStep("set customized mod externally", () => SelectedMods.Value = new[] { new OsuModDoubleTime { SpeedChange = { Value = 1.01 } } });
+
+            AddAssert("ensure button is selected and customized accordingly", () =>
+            {
+                var button = getPanelForMod(SelectedMods.Value.Single().GetType());
+                return ((OsuModDoubleTime)button.Mod).SpeedChange.Value == 1.01;
+            });
+        }
+
+        [Test]
+        public void TestSettingsAreRetainedOnReload()
+        {
+            createScreen();
+            changeRuleset(0);
+
+            AddStep("set customized mod externally", () => SelectedMods.Value = new[] { new OsuModDoubleTime { SpeedChange = { Value = 1.01 } } });
+            AddAssert("setting remains", () => (SelectedMods.Value.SingleOrDefault() as OsuModDoubleTime)?.SpeedChange.Value == 1.01);
+
+            createScreen();
+            AddAssert("setting remains", () => (SelectedMods.Value.SingleOrDefault() as OsuModDoubleTime)?.SpeedChange.Value == 1.01);
+        }
+
+        [Test]
+        public void TestExternallySetModIsReplacedByOverlayInstance()
+        {
+            Mod external = new OsuModDoubleTime();
+            Mod overlayButtonMod = null;
+
+            createScreen();
+            changeRuleset(0);
+
+            AddStep("set mod externally", () => { SelectedMods.Value = new[] { external }; });
+
+            AddAssert("ensure button is selected", () =>
+            {
+                var button = getPanelForMod(SelectedMods.Value.Single().GetType());
+                overlayButtonMod = button.Mod;
+                return button.Active.Value;
+            });
+
+            // Right now, when an external change occurs, the ModSelectOverlay will replace the global instance with its own
+            AddAssert("mod instance doesn't match", () => external != overlayButtonMod);
+
+            AddAssert("one mod present in global selected", () => SelectedMods.Value.Count == 1);
+            AddAssert("globally selected matches button's mod instance", () => SelectedMods.Value.Any(mod => ReferenceEquals(mod, overlayButtonMod)));
+            AddAssert("globally selected doesn't contain original external change", () => !SelectedMods.Value.Any(mod => ReferenceEquals(mod, external)));
+        }
+
+        [Test]
+        public void TestChangeIsValidChangesButtonVisibility()
+        {
+            createScreen();
+            changeRuleset(0);
+
+            AddAssert("double time visible", () => modSelectScreen.ChildrenOfType<ModPanel>().Where(panel => panel.Mod is OsuModDoubleTime).Any(panel => !panel.Filtered.Value));
+
+            AddStep("make double time invalid", () => modSelectScreen.IsValidMod = m => !(m is OsuModDoubleTime));
+            AddUntilStep("double time not visible", () => modSelectScreen.ChildrenOfType<ModPanel>().Where(panel => panel.Mod is OsuModDoubleTime).All(panel => panel.Filtered.Value));
+            AddAssert("nightcore still visible", () => modSelectScreen.ChildrenOfType<ModPanel>().Where(panel => panel.Mod is OsuModNightcore).Any(panel => !panel.Filtered.Value));
+
+            AddStep("make double time valid again", () => modSelectScreen.IsValidMod = m => true);
+            AddUntilStep("double time visible", () => modSelectScreen.ChildrenOfType<ModPanel>().Where(panel => panel.Mod is OsuModDoubleTime).Any(panel => !panel.Filtered.Value));
+            AddAssert("nightcore still visible", () => modSelectScreen.ChildrenOfType<ModPanel>().Where(b => b.Mod is OsuModNightcore).Any(panel => !panel.Filtered.Value));
+        }
+
+        [Test]
+        public void TestChangeIsValidPreservesSelection()
+        {
+            createScreen();
+            changeRuleset(0);
+
+            AddStep("select DT + HD", () => SelectedMods.Value = new Mod[] { new OsuModDoubleTime(), new OsuModHidden() });
+            AddAssert("DT + HD selected", () => modSelectScreen.ChildrenOfType<ModPanel>().Count(panel => panel.Active.Value) == 2);
+
+            AddStep("make NF invalid", () => modSelectScreen.IsValidMod = m => !(m is ModNoFail));
+            AddAssert("DT + HD still selected", () => modSelectScreen.ChildrenOfType<ModPanel>().Count(panel => panel.Active.Value) == 2);
+        }
+
+        [Test]
+        public void TestUnimplementedModIsUnselectable()
+        {
+            var testRuleset = new TestUnimplementedModOsuRuleset();
+
+            createScreen();
+
+            AddStep("set ruleset", () => Ruleset.Value = testRuleset.RulesetInfo);
+            waitForColumnLoad();
+
+            AddAssert("unimplemented mod panel is filtered", () => getPanelForMod(typeof(TestUnimplementedMod)).Filtered.Value);
+        }
+
         private void waitForColumnLoad() => AddUntilStep("all column content loaded",
             () => modSelectScreen.ChildrenOfType<ModColumn>().Any() && modSelectScreen.ChildrenOfType<ModColumn>().All(column => column.IsLoaded && column.ItemsLoaded));
 
@@ -188,5 +402,26 @@ namespace osu.Game.Tests.Visual.UserInterface
 
         private ModPanel getPanelForMod(Type modType)
             => modSelectScreen.ChildrenOfType<ModPanel>().Single(panel => panel.Mod.GetType() == modType);
+
+        private class TestUnimplementedMod : Mod
+        {
+            public override string Name => "Unimplemented mod";
+            public override string Acronym => "UM";
+            public override string Description => "A mod that is not implemented.";
+            public override double ScoreMultiplier => 1;
+            public override ModType Type => ModType.Conversion;
+        }
+
+        private class TestUnimplementedModOsuRuleset : OsuRuleset
+        {
+            public override string ShortName => "unimplemented";
+
+            public override IEnumerable<Mod> GetModsFor(ModType type)
+            {
+                if (type == ModType.Conversion) return base.GetModsFor(type).Concat(new[] { new TestUnimplementedMod() });
+
+                return base.GetModsFor(type);
+            }
+        }
     }
 }

osu.Game/Beatmaps/BeatmapInfo.cs

@@ -1,21 +1,23 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+#nullable enable
+
 using System;
 using System.Linq;
 using JetBrains.Annotations;
 using Newtonsoft.Json;
 using osu.Framework.Testing;
+using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Database;
 using osu.Game.Models;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Overlays.BeatmapSet.Scores;
 using osu.Game.Rulesets;
+using osu.Game.Rulesets.Edit;
 using osu.Game.Scoring;
 using Realms;
 
-#nullable enable
-
 namespace osu.Game.Beatmaps
 {
     /// <summary>
@@ -109,6 +111,16 @@ namespace osu.Game.Beatmaps
 
         public bool SamplesMatchPlaybackRate { get; set; } = true;
 
+        /// <summary>
+        /// The ratio of distance travelled per time unit.
+        /// Generally used to decouple the spacing between hit objects from the enforced "velocity" of the beatmap (see <see cref="DifficultyControlPoint.SliderVelocity"/>).
+        /// </summary>
+        /// <remarks>
+        /// The most common method of understanding is that at a default value of 1.0, the time-to-distance ratio will match the slider velocity of the beatmap
+        /// at the current point in time. Increasing this value will make hit objects more spaced apart when compared to the cursor movement required to track a slider.
+        ///
+        /// This is only a hint property, used by the editor in <see cref="IDistanceSnapProvider"/> implementations. It does not directly affect the beatmap or gameplay.
+        /// </remarks>
         public double DistanceSpacing { get; set; } = 1.0;
 
         public int BeatDivisor { get; set; }

osu.Game/Beatmaps/BeatmapOnlineLookupQueue.cs

@@ -153,7 +153,7 @@ namespace osu.Game.Beatmaps
                 }
             };
 
-            cacheDownloadRequest.PerformAsync();
+            Task.Run(() => cacheDownloadRequest.PerformAsync());
         }
 
         private bool checkLocalCache(BeatmapSetInfo set, BeatmapInfo beatmapInfo)

osu.Game/Input/Bindings/GlobalActionContainer.cs

@@ -59,6 +59,9 @@ namespace osu.Game.Input.Bindings
             new KeyBinding(InputKey.Up, GlobalAction.SelectPrevious),
             new KeyBinding(InputKey.Down, GlobalAction.SelectNext),
 
+            new KeyBinding(InputKey.Left, GlobalAction.SelectPreviousGroup),
+            new KeyBinding(InputKey.Right, GlobalAction.SelectNextGroup),
+
             new KeyBinding(InputKey.Space, GlobalAction.Select),
             new KeyBinding(InputKey.Enter, GlobalAction.Select),
             new KeyBinding(InputKey.KeypadEnter, GlobalAction.Select),
@@ -105,7 +108,7 @@ namespace osu.Game.Input.Bindings
             new KeyBinding(InputKey.F1, GlobalAction.ToggleModSelection),
             new KeyBinding(InputKey.F2, GlobalAction.SelectNextRandom),
             new KeyBinding(new[] { InputKey.Shift, InputKey.F2 }, GlobalAction.SelectPreviousRandom),
-            new KeyBinding(InputKey.F3, GlobalAction.ToggleBeatmapOptions)
+            new KeyBinding(InputKey.F3, GlobalAction.ToggleBeatmapOptions),
         };
 
         public IEnumerable<KeyBinding> AudioControlKeyBindings => new[]
@@ -309,5 +312,11 @@ namespace osu.Game.Input.Bindings
 
         [LocalisableDescription(typeof(GlobalActionKeyBindingStrings), nameof(GlobalActionKeyBindingStrings.EditorDecreaseDistanceSpacing))]
         EditorDecreaseDistanceSpacing,
+
+        [LocalisableDescription(typeof(GlobalActionKeyBindingStrings), nameof(GlobalActionKeyBindingStrings.SelectPreviousGroup))]
+        SelectPreviousGroup,
+
+        [LocalisableDescription(typeof(GlobalActionKeyBindingStrings), nameof(GlobalActionKeyBindingStrings.SelectNextGroup))]
+        SelectNextGroup,
     }
 }

osu.Game/Localisation/GlobalActionKeyBindingStrings.cs

@@ -129,6 +129,16 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString SelectNext => new TranslatableString(getKey(@"select_next"), @"Next selection");
 
+        /// <summary>
+        /// "Select previous group"
+        /// </summary>
+        public static LocalisableString SelectPreviousGroup => new TranslatableString(getKey(@"select_previous_group"), @"Select previous group");
+
+        /// <summary>
+        /// "Select next group"
+        /// </summary>
+        public static LocalisableString SelectNextGroup => new TranslatableString(getKey(@"select_next_group"), @"Select next group");
+
         /// <summary>
         /// "Home"
         /// </summary>

osu.Game/Overlays/Mods/ModColumn.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -10,6 +12,7 @@ using Humanizer;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Colour;
 using osu.Framework.Graphics.Containers;
@@ -25,8 +28,6 @@ using osuTK;
 using osuTK.Graphics;
 using osuTK.Input;
 
-#nullable enable
-
 namespace osu.Game.Overlays.Mods
 {
     public class ModColumn : CompositeDrawable
@@ -52,9 +53,22 @@ namespace osu.Game.Overlays.Mods
             }
         }
 
-        public Bindable<IReadOnlyList<Mod>> SelectedMods = new Bindable<IReadOnlyList<Mod>>(Array.Empty<Mod>());
         public Bindable<bool> Active = new BindableBool(true);
 
+        /// <summary>
+        /// List of mods marked as selected in this column.
+        /// </summary>
+        /// <remarks>
+        /// Note that the mod instances returned by this property are owned solely by this column
+        /// (as in, they are locally-managed clones, to ensure proper isolation from any other external instances).
+        /// </remarks>
+        public IReadOnlyList<Mod> SelectedMods { get; private set; } = Array.Empty<Mod>();
+
+        /// <summary>
+        /// Invoked when a mod panel has been selected interactively by the user.
+        /// </summary>
+        public event Action? SelectionChangedByUser;
+
         protected override bool ReceivePositionalInputAtSubTree(Vector2 screenSpacePos) => base.ReceivePositionalInputAtSubTree(screenSpacePos) && Active.Value;
 
         protected virtual ModPanel CreateModPanel(Mod mod) => new ModPanel(mod);
@@ -63,6 +77,15 @@ namespace osu.Game.Overlays.Mods
 
         private readonly Bindable<Dictionary<ModType, IReadOnlyList<Mod>>> availableMods = new Bindable<Dictionary<ModType, IReadOnlyList<Mod>>>();
 
+        /// <summary>
+        /// All mods that are available for the current ruleset in this particular column.
+        /// </summary>
+        /// <remarks>
+        /// Note that the mod instances in this list are owned solely by this column
+        /// (as in, they are locally-managed clones, to ensure proper isolation from any other external instances).
+        /// </remarks>
+        private IReadOnlyList<Mod> localAvailableMods = Array.Empty<Mod>();
+
         private readonly TextFlowContainer headerText;
         private readonly Box headerBackground;
         private readonly Container contentContainer;
@@ -226,6 +249,9 @@ namespace osu.Game.Overlays.Mods
         private void load(OsuGameBase game, OverlayColourProvider colourProvider, OsuColour colours)
         {
             availableMods.BindTo(game.AvailableMods);
+            // this `BindValueChanged` callback is intentionally here, to ensure that local available mods are constructed as early as possible.
+            // this is needed to make sure no external changes to mods are dropped while mod panels are asynchronously loading.
+            availableMods.BindValueChanged(_ => updateLocalAvailableMods(), true);
 
             headerBackground.Colour = accentColour = colours.ForModType(ModType);
 
@@ -239,31 +265,26 @@ namespace osu.Game.Overlays.Mods
             contentBackground.Colour = colourProvider.Background4;
         }
 
-        protected override void LoadComplete()
+        private void updateLocalAvailableMods()
         {
-            base.LoadComplete();
+            var newMods = ModUtils.FlattenMods(availableMods.Value.GetValueOrDefault(ModType) ?? Array.Empty<Mod>())
-            availableMods.BindValueChanged(_ => Scheduler.AddOnce(updateMods));
+                                  .Select(m => m.DeepClone())
-            SelectedMods.BindValueChanged(_ =>
+                                  .ToList();
-            {
+
-                // if a load is in progress, don't try to update the selection - the load flow will do so.
+            if (newMods.SequenceEqual(localAvailableMods))
-                if (latestLoadTask == null)
+                return;
-                    updateActiveState();
+
-            });
+            localAvailableMods = newMods;
-            updateMods();
+            Scheduler.AddOnce(loadPanels);
         }
 
         private CancellationTokenSource? cancellationTokenSource;
 
-        private void updateMods()
+        private void loadPanels()
         {
-            var newMods = ModUtils.FlattenMods(availableMods.Value.GetValueOrDefault(ModType) ?? Array.Empty<Mod>()).ToList();
-
-            if (newMods.SequenceEqual(panelFlow.Children.Select(p => p.Mod)))
-                return;
-
             cancellationTokenSource?.Cancel();
 
-            var panels = newMods.Select(mod => CreateModPanel(mod).With(panel => panel.Shear = new Vector2(-ShearedOverlayContainer.SHEAR, 0)));
+            var panels = localAvailableMods.Select(mod => CreateModPanel(mod).With(panel => panel.Shear = new Vector2(-ShearedOverlayContainer.SHEAR, 0)));
 
             Task? loadTask;
 
@@ -277,13 +298,7 @@ namespace osu.Game.Overlays.Mods
 
                 foreach (var panel in panelFlow)
                 {
-                    panel.Active.BindValueChanged(_ =>
+                    panel.Active.BindValueChanged(_ => panelStateChanged(panel));
-                    {
-                        updateToggleAllState();
-                        SelectedMods.Value = panel.Active.Value
-                            ? SelectedMods.Value.Append(panel.Mod).ToArray()
-                            : SelectedMods.Value.Except(new[] { panel.Mod }).ToArray();
-                    });
                 }
             }, (cancellationTokenSource = new CancellationTokenSource()).Token);
             loadTask.ContinueWith(_ =>
@@ -296,7 +311,62 @@ namespace osu.Game.Overlays.Mods
         private void updateActiveState()
         {
             foreach (var panel in panelFlow)
-                panel.Active.Value = SelectedMods.Value.Contains(panel.Mod, EqualityComparer<Mod>.Default);
+                panel.Active.Value = SelectedMods.Contains(panel.Mod);
+        }
+
+        /// <summary>
+        /// This flag helps to determine the source of changes to <see cref="SelectedMods"/>.
+        /// If the value is false, then <see cref="SelectedMods"/> are changing due to a user selection on the UI.
+        /// If the value is true, then <see cref="SelectedMods"/> are changing due to an external <see cref="SetSelection"/> call.
+        /// </summary>
+        private bool externalSelectionUpdateInProgress;
+
+        private void panelStateChanged(ModPanel panel)
+        {
+            updateToggleAllState();
+
+            var newSelectedMods = panel.Active.Value
+                ? SelectedMods.Append(panel.Mod)
+                : SelectedMods.Except(panel.Mod.Yield());
+
+            SelectedMods = newSelectedMods.ToArray();
+            if (!externalSelectionUpdateInProgress)
+                SelectionChangedByUser?.Invoke();
+        }
+
+        /// <summary>
+        /// Adjusts the set of selected mods in this column to match the passed in <paramref name="mods"/>.
+        /// </summary>
+        /// <remarks>
+        /// This method exists to be able to receive mod instances that come from potentially-external sources and to copy the changes across to this column's state.
+        /// <see cref="ModSelectScreen"/> uses this to substitute any external mod references in <see cref="ModSelectScreen.SelectedMods"/>
+        /// to references that are owned by this column.
+        /// </remarks>
+        internal void SetSelection(IReadOnlyList<Mod> mods)
+        {
+            externalSelectionUpdateInProgress = true;
+
+            var newSelection = new List<Mod>();
+
+            foreach (var mod in localAvailableMods)
+            {
+                var matchingSelectedMod = mods.SingleOrDefault(selected => selected.GetType() == mod.GetType());
+
+                if (matchingSelectedMod != null)
+                {
+                    mod.CopyFrom(matchingSelectedMod);
+                    newSelection.Add(mod);
+                }
+                else
+                {
+                    mod.ResetSettingsToDefaults();
+                }
+            }
+
+            SelectedMods = newSelection;
+            updateActiveState();
+
+            externalSelectionUpdateInProgress = false;
         }
 
         #region Bulk select / deselect
@@ -364,6 +434,15 @@ namespace osu.Game.Overlays.Mods
                 pendingSelectionOperations.Enqueue(() => button.Active.Value = false);
         }
 
+        /// <summary>
+        /// Run any delayed selections (due to animation) immediately to leave mods in a good (final) state.
+        /// </summary>
+        public void FlushPendingSelections()
+        {
+            while (pendingSelectionOperations.TryDequeue(out var dequeuedAction))
+                dequeuedAction();
+        }
+
         private class ToggleAllCheckbox : OsuCheckbox
         {
             private Color4 accentColour;

osu.Game/Overlays/Mods/ModSection.cs

@@ -250,9 +250,9 @@ namespace osu.Game.Overlays.Mods
         protected virtual ModButton CreateModButton(Mod mod) => new ModButton(mod);
 
         /// <summary>
-        /// Play out all remaining animations immediately to leave mods in a good (final) state.
+        /// Run any delayed selections (due to animation) immediately to leave mods in a good (final) state.
         /// </summary>
-        public void FlushAnimation()
+        public void FlushPendingSelections()
         {
             while (pendingSelectionOperations.TryDequeue(out var dequeuedAction))
                 dequeuedAction();

osu.Game/Overlays/Mods/ModSelectOverlay.cs

@@ -369,7 +369,7 @@ namespace osu.Game.Overlays.Mods
 
             foreach (var section in ModSectionsContainer)
             {
-                section.FlushAnimation();
+                section.FlushPendingSelections();
             }
 
             FooterContainer.MoveToX(content_width, WaveContainer.DISAPPEAR_DURATION, Easing.InSine);

osu.Game/Overlays/Mods/ModSelectScreen.cs

@@ -179,7 +179,7 @@ namespace osu.Game.Overlays.Mods
 
             foreach (var column in columnFlow.Columns)
             {
-                column.SelectedMods.BindValueChanged(updateBindableFromSelection);
+                column.SelectionChangedByUser += updateBindableFromSelection;
             }
 
             customisationVisible.BindValueChanged(_ => updateCustomisationVisualState(), true);
@@ -203,7 +203,7 @@ namespace osu.Game.Overlays.Mods
         private void updateAvailableMods()
         {
             foreach (var column in columnFlow.Columns)
-                column.Filter = isValidMod;
+                column.Filter = m => m.HasImplementation && isValidMod.Invoke(m);
         }
 
         private void updateCustomisation(ValueChangedEvent<IReadOnlyList<Mod>> valueChangedEvent)
@@ -250,33 +250,26 @@ namespace osu.Game.Overlays.Mods
 
         private void updateSelectionFromBindable()
         {
-            // note that selectionBindableSyncInProgress is purposefully not checked here.
+            // `SelectedMods` may contain mod references that come from external sources.
-            // this is because in the case of mod selection in solo gameplay, a user selection of a mod can actually lead to deselection of other incompatible mods.
+            // to ensure isolation, first pull in the potentially-external change into the mod columns...
-            // to synchronise state correctly, updateBindableFromSelection() computes the final mods (including incompatibility rules) and updates SelectedMods,
-            // and this method then runs unconditionally again to make sure the new visual selection accurately reflects the final set of selected mods.
-            // selectionBindableSyncInProgress ensures that mutual infinite recursion does not happen after that unconditional call.
             foreach (var column in columnFlow.Columns)
-                column.SelectedMods.Value = SelectedMods.Value.Where(mod => mod.Type == column.ModType).ToArray();
+                column.SetSelection(SelectedMods.Value);
+
+            // and then, when done, replace the potentially-external mod references in `SelectedMods` with ones we own.
+            updateBindableFromSelection();
         }
 
-        private bool selectionBindableSyncInProgress;
+        private void updateBindableFromSelection()
-
-        private void updateBindableFromSelection(ValueChangedEvent<IReadOnlyList<Mod>> modSelectionChange)
         {
-            if (selectionBindableSyncInProgress)
+            var candidateSelection = columnFlow.Columns.SelectMany(column => column.SelectedMods).ToArray();
+
+            if (candidateSelection.SequenceEqual(SelectedMods.Value))
                 return;
 
-            selectionBindableSyncInProgress = true;
+            SelectedMods.Value = ComputeNewModsFromSelection(SelectedMods.Value, candidateSelection);
-
-            SelectedMods.Value = ComputeNewModsFromSelection(
-                modSelectionChange.NewValue.Except(modSelectionChange.OldValue),
-                modSelectionChange.OldValue.Except(modSelectionChange.NewValue));
-
-            selectionBindableSyncInProgress = false;
         }
 
-        protected virtual IReadOnlyList<Mod> ComputeNewModsFromSelection(IEnumerable<Mod> addedMods, IEnumerable<Mod> removedMods)
+        protected virtual IReadOnlyList<Mod> ComputeNewModsFromSelection(IReadOnlyList<Mod> oldSelection, IReadOnlyList<Mod> newSelection) => newSelection;
-            => columnFlow.Columns.SelectMany(column => column.SelectedMods.Value).ToArray();
 
         protected override void PopIn()
         {
@@ -313,10 +306,12 @@ namespace osu.Game.Overlays.Mods
             {
                 const float distance = 700;
 
-                columnFlow[i].Column
+                var column = columnFlow[i].Column;
-                             .TopLevelContent
+
-                             .MoveToY(i % 2 == 0 ? -distance : distance, fade_out_duration, Easing.OutQuint)
+                column.FlushPendingSelections();
-                             .FadeOut(fade_out_duration, Easing.OutQuint);
+                column.TopLevelContent
+                      .MoveToY(i % 2 == 0 ? -distance : distance, fade_out_duration, Easing.OutQuint)
+                      .FadeOut(fade_out_duration, Easing.OutQuint);
             }
         }
 

osu.Game/Overlays/Mods/ModSettingsArea.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
@@ -21,7 +22,7 @@ namespace osu.Game.Overlays.Mods
 {
     public class ModSettingsArea : CompositeDrawable
     {
-        public Bindable<IReadOnlyList<Mod>> SelectedMods { get; } = new Bindable<IReadOnlyList<Mod>>();
+        public Bindable<IReadOnlyList<Mod>> SelectedMods { get; } = new Bindable<IReadOnlyList<Mod>>(Array.Empty<Mod>());
 
         public const float HEIGHT = 250;
 
@@ -77,7 +78,7 @@ namespace osu.Game.Overlays.Mods
         protected override void LoadComplete()
         {
             base.LoadComplete();
-            SelectedMods.BindValueChanged(_ => updateMods());
+            SelectedMods.BindValueChanged(_ => updateMods(), true);
         }
 
         private void updateMods()

osu.Game/Overlays/Mods/UserModSelectScreen.cs

@@ -14,9 +14,12 @@ namespace osu.Game.Overlays.Mods
     {
         protected override ModColumn CreateModColumn(ModType modType, Key[] toggleKeys = null) => new UserModColumn(modType, false, toggleKeys);
 
-        protected override IReadOnlyList<Mod> ComputeNewModsFromSelection(IEnumerable<Mod> addedMods, IEnumerable<Mod> removedMods)
+        protected override IReadOnlyList<Mod> ComputeNewModsFromSelection(IReadOnlyList<Mod> oldSelection, IReadOnlyList<Mod> newSelection)
         {
-            IEnumerable<Mod> modsAfterRemoval = SelectedMods.Value.Except(removedMods).ToList();
+            var addedMods = newSelection.Except(oldSelection);
+            var removedMods = oldSelection.Except(newSelection);
+
+            IEnumerable<Mod> modsAfterRemoval = newSelection.Except(removedMods).ToList();
 
             // the preference is that all new mods should override potential incompatible old mods.
             // in general that's a bit difficult to compute if more than one mod is added at a time,

osu.Game/Overlays/Volume/VolumeMeter.cs

@@ -372,12 +372,12 @@ namespace osu.Game.Overlays.Volume
 
             switch (e.Action)
             {
-                case GlobalAction.SelectPrevious:
+                case GlobalAction.SelectPreviousGroup:
                     State = SelectionState.Selected;
                     adjust(1, false);
                     return true;
 
-                case GlobalAction.SelectNext:
+                case GlobalAction.SelectNextGroup:
                     State = SelectionState.Selected;
                     adjust(-1, false);
                     return true;

osu.Game/Rulesets/Edit/DistancedHitObjectComposer.cs

@@ -10,14 +10,12 @@ using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Events;
 using osu.Framework.Localisation;
 using osu.Game.Configuration;
-using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Input.Bindings;
 using osu.Game.Overlays;
 using osu.Game.Overlays.OSD;
 using osu.Game.Overlays.Settings.Sections;
 using osu.Game.Rulesets.Objects;
-using osuTK;
 
 namespace osu.Game.Rulesets.Edit
 {
@@ -25,7 +23,6 @@ namespace osu.Game.Rulesets.Edit
     /// Represents a <see cref="HitObjectComposer{TObject}"/> for rulesets with the concept of distances between objects.
     /// </summary>
     /// <typeparam name="TObject">The base type of supported objects.</typeparam>
-    [Cached(typeof(IDistanceSnapProvider))]
     public abstract class DistancedHitObjectComposer<TObject> : HitObjectComposer<TObject>, IDistanceSnapProvider, IScrollBindingHandler<GlobalAction>
         where TObject : HitObject
     {
@@ -53,8 +50,9 @@ namespace osu.Game.Rulesets.Edit
         [BackgroundDependencyLoader]
         private void load()
         {
-            AddInternal(RightSideToolboxContainer = new ExpandingToolboxContainer
+            AddInternal(RightSideToolboxContainer = new ExpandingToolboxContainer(130, 250)
             {
+                Padding = new MarginPadding { Right = 10 },
                 Alpha = DistanceSpacingMultiplier.Disabled ? 0 : 1,
                 Anchor = Anchor.TopRight,
                 Origin = Anchor.TopRight,
@@ -147,10 +145,10 @@ namespace osu.Game.Rulesets.Edit
             return distance / GetBeatSnapDistanceAt(referenceObject) * beatLength;
         }
 
-        public virtual double GetSnappedDurationFromDistance(HitObject referenceObject, float distance)
+        public virtual double FindSnappedDuration(HitObject referenceObject, float distance)
             => BeatSnapProvider.SnapTime(referenceObject.StartTime + DistanceToDuration(referenceObject, distance), referenceObject.StartTime) - referenceObject.StartTime;
 
-        public virtual float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance)
+        public virtual float FindSnappedDistance(HitObject referenceObject, float distance)
         {
             double startTime = referenceObject.StartTime;
 
@@ -168,20 +166,6 @@ namespace osu.Game.Rulesets.Edit
             return DurationToDistance(referenceObject, snappedEndTime - startTime);
         }
 
-        protected class ExpandingToolboxContainer : ExpandingContainer
-        {
-            protected override double HoverExpansionDelay => 250;
-
-            public ExpandingToolboxContainer()
-                : base(130, 250)
-            {
-                RelativeSizeAxes = Axes.Y;
-                Padding = new MarginPadding { Left = 10 };
-
-                FillFlow.Spacing = new Vector2(10);
-            }
-        }
-
         private class DistanceSpacingToast : Toast
         {
             private readonly ValueChangedEvent<double> change;

osu.Game/Rulesets/Edit/ExpandingToolboxContainer.cs

@@ -0,0 +1,34 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using osu.Framework.Graphics;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics.Containers;
+using osuTK;
+
+namespace osu.Game.Rulesets.Edit
+{
+    public class ExpandingToolboxContainer : ExpandingContainer
+    {
+        protected override double HoverExpansionDelay => 250;
+
+        public ExpandingToolboxContainer(float contractedWidth, float expandedWidth)
+            : base(contractedWidth, expandedWidth)
+        {
+            RelativeSizeAxes = Axes.Y;
+
+            FillFlow.Spacing = new Vector2(10);
+        }
+
+        protected override bool ReceivePositionalInputAtSubTree(Vector2 screenSpacePos) => base.ReceivePositionalInputAtSubTree(screenSpacePos) && anyToolboxHovered(screenSpacePos);
+
+        public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => base.ReceivePositionalInputAt(screenSpacePos) && anyToolboxHovered(screenSpacePos);
+
+        private bool anyToolboxHovered(Vector2 screenSpacePos) => FillFlow.Children.Any(d => d.ScreenSpaceDrawQuad.Contains(screenSpacePos));
+
+        protected override bool OnMouseDown(MouseDownEvent e) => true;
+
+        protected override bool OnClick(ClickEvent e) => true;
+    }
+}

osu.Game/Rulesets/Edit/HitObjectComposer.cs

@@ -13,7 +13,6 @@ using osu.Framework.Input;
 using osu.Framework.Input.Events;
 using osu.Framework.Logging;
 using osu.Game.Beatmaps;
-using osu.Game.Graphics.Containers;
 using osu.Game.Rulesets.Configuration;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mods;
@@ -36,7 +35,6 @@ namespace osu.Game.Rulesets.Edit
     /// Responsible for providing snapping and generally gluing components together.
     /// </summary>
     /// <typeparam name="TObject">The base type of supported objects.</typeparam>
-    [Cached(Type = typeof(IPlacementHandler))]
     public abstract class HitObjectComposer<TObject> : HitObjectComposer, IPlacementHandler
         where TObject : HitObject
     {
@@ -115,8 +113,9 @@ namespace osu.Game.Rulesets.Edit
                                               .WithChild(BlueprintContainer = CreateBlueprintContainer())
                     }
                 },
-                new LeftToolboxFlow
+                new ExpandingToolboxContainer(80, 200)
                 {
+                    Padding = new MarginPadding { Left = 10 },
                     Children = new Drawable[]
                     {
                         new EditorToolboxGroup("toolbox (1-9)")
@@ -362,7 +361,7 @@ namespace osu.Game.Rulesets.Edit
         /// <returns>The most relevant <see cref="Playfield"/>.</returns>
         protected virtual Playfield PlayfieldAtScreenSpacePosition(Vector2 screenSpacePosition) => drawableRulesetWrapper.Playfield;
 
-        public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
+        public override SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition)
         {
             var playfield = PlayfieldAtScreenSpacePosition(screenSpacePosition);
             double? targetTime = null;
@@ -382,26 +381,13 @@ namespace osu.Game.Rulesets.Edit
         }
 
         #endregion
-
-        private class LeftToolboxFlow : ExpandingButtonContainer
-        {
-            public LeftToolboxFlow()
-                : base(80, 200)
-            {
-                RelativeSizeAxes = Axes.Y;
-                Padding = new MarginPadding { Right = 10 };
-
-                FillFlow.Spacing = new Vector2(10);
-            }
-        }
     }
 
     /// <summary>
     /// A non-generic definition of a HitObject composer class.
     /// Generally used to access certain methods without requiring a generic type for <see cref="HitObjectComposer{T}" />.
     /// </summary>
-    [Cached(typeof(HitObjectComposer))]
+    [Cached]
-    [Cached(typeof(IPositionSnapProvider))]
     public abstract class HitObjectComposer : CompositeDrawable, IPositionSnapProvider
     {
         protected HitObjectComposer()
@@ -428,9 +414,9 @@ namespace osu.Game.Rulesets.Edit
 
         #region IPositionSnapProvider
 
-        public abstract SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition);
+        public abstract SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition);
 
-        public virtual SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition) =>
+        public virtual SnapResult FindSnappedPosition(Vector2 screenSpacePosition) =>
             new SnapResult(screenSpacePosition, null);
 
         #endregion

osu.Game/Rulesets/Edit/IDistanceSnapProvider.cs

@@ -1,16 +1,21 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Objects;
 
 namespace osu.Game.Rulesets.Edit
 {
+    /// <summary>
+    /// A snap provider which given a reference hit object and proposed distance from it, offers a more correct duration or distance value.
+    /// </summary>
+    [Cached]
     public interface IDistanceSnapProvider : IPositionSnapProvider
     {
         /// <summary>
-        /// The spacing multiplier applied to beat snap distances.
+        /// A multiplier which changes the ratio of distance travelled per time unit.
         /// </summary>
         /// <seealso cref="BeatmapInfo.DistanceSpacing"/>
         IBindable<double> DistanceSpacingMultiplier { get; }
@@ -23,7 +28,7 @@ namespace osu.Game.Rulesets.Edit
         float GetBeatSnapDistanceAt(HitObject referenceObject);
 
         /// <summary>
-        /// Converts a duration to a distance.
+        /// Converts a duration to a distance without applying any snapping.
         /// </summary>
         /// <param name="referenceObject">An object to be used as a reference point for this operation.</param>
         /// <param name="duration">The duration to convert.</param>
@@ -31,7 +36,7 @@ namespace osu.Game.Rulesets.Edit
         float DurationToDistance(HitObject referenceObject, double duration);
 
         /// <summary>
-        /// Converts a distance to a duration.
+        /// Converts a distance to a duration without applying any snapping.
         /// </summary>
         /// <param name="referenceObject">An object to be used as a reference point for this operation.</param>
         /// <param name="distance">The distance to convert.</param>
@@ -39,20 +44,22 @@ namespace osu.Game.Rulesets.Edit
         double DistanceToDuration(HitObject referenceObject, float distance);
 
         /// <summary>
-        /// Converts a distance to a snapped duration.
+        /// Given a distance from the provided hit object, find the valid snapped duration.
         /// </summary>
         /// <param name="referenceObject">An object to be used as a reference point for this operation.</param>
         /// <param name="distance">The distance to convert.</param>
         /// <returns>A value that represents <paramref name="distance"/> as a duration snapped to the closest beat of the timing point.</returns>
-        double GetSnappedDurationFromDistance(HitObject referenceObject, float distance);
+        double FindSnappedDuration(HitObject referenceObject, float distance);
 
         /// <summary>
-        /// Converts an unsnapped distance to a snapped distance.
+        /// Given a distance from the provided hit object, find the valid snapped distance.
-        /// The returned distance will always be floored (as to never exceed the provided <paramref name="distance"/>.
         /// </summary>
         /// <param name="referenceObject">An object to be used as a reference point for this operation.</param>
         /// <param name="distance">The distance to convert.</param>
-        /// <returns>A value that represents <paramref name="distance"/> snapped to the closest beat of the timing point.</returns>
+        /// <returns>
-        float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance);
+        /// A value that represents <paramref name="distance"/> snapped to the closest beat of the timing point.
+        /// The distance will always be less than or equal to the provided <paramref name="distance"/>.
+        /// </returns>
+        float FindSnappedDistance(HitObject referenceObject, float distance);
     }
 }

osu.Game/Rulesets/Edit/IPositionSnapProvider.cs

@@ -1,27 +1,33 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
 using osuTK;
 
 namespace osu.Game.Rulesets.Edit
 {
+    /// <summary>
+    /// A snap provider which given a proposed position for a hit object, potentially offers a more correct position and time value inferred from the context of the beatmap.
+    /// Provided values are inferred in an isolated context, without consideration of other nearby hit objects.
+    /// </summary>
+    [Cached]
     public interface IPositionSnapProvider
     {
         /// <summary>
         /// Given a position, find a valid time and position snap.
         /// </summary>
         /// <remarks>
-        /// This call should be equivalent to running <see cref="SnapScreenSpacePositionToValidPosition"/> with any additional logic that can be performed without the time immutability restriction.
+        /// This call should be equivalent to running <see cref="FindSnappedPosition"/> with any additional logic that can be performed without the time immutability restriction.
         /// </remarks>
         /// <param name="screenSpacePosition">The screen-space position to be snapped.</param>
         /// <returns>The time and position post-snapping.</returns>
-        SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition);
+        SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition);
 
         /// <summary>
-        /// Given a position, find a value position snap, restricting time to its input value.
+        /// Given a position, find a valid position snap, without changing the time value.
         /// </summary>
         /// <param name="screenSpacePosition">The screen-space position to be snapped.</param>
         /// <returns>The position post-snapping. Time will always be null.</returns>
-        SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition);
+        SnapResult FindSnappedPosition(Vector2 screenSpacePosition);
     }
 }

osu.Game/Rulesets/Edit/ScrollingToolboxGroup.cs

@@ -1,34 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Game.Graphics.Containers;
-
-namespace osu.Game.Rulesets.Edit
-{
-    public class ScrollingToolboxGroup : EditorToolboxGroup
-    {
-        protected readonly OsuScrollContainer Scroll;
-
-        protected readonly FillFlowContainer FillFlow;
-
-        protected override Container<Drawable> Content { get; }
-
-        public ScrollingToolboxGroup(string title, float scrollAreaHeight)
-            : base(title)
-        {
-            base.Content.Add(Scroll = new OsuScrollContainer
-            {
-                RelativeSizeAxes = Axes.X,
-                Height = scrollAreaHeight,
-                Child = Content = FillFlow = new FillFlowContainer
-                {
-                    RelativeSizeAxes = Axes.X,
-                    AutoSizeAxes = Axes.Y,
-                    Direction = FillDirection.Vertical,
-                },
-            });
-        }
-    }
-}

osu.Game/Rulesets/Objects/SliderPathExtensions.cs

@@ -18,7 +18,7 @@ namespace osu.Game.Rulesets.Objects
         public static void SnapTo<THitObject>(this THitObject hitObject, IDistanceSnapProvider? snapProvider)
             where THitObject : HitObject, IHasPath
         {
-            hitObject.Path.ExpectedDistance.Value = snapProvider?.GetSnappedDistanceFromDistance(hitObject, (float)hitObject.Path.CalculatedDistance) ?? hitObject.Path.CalculatedDistance;
+            hitObject.Path.ExpectedDistance.Value = snapProvider?.FindSnappedDistance(hitObject, (float)hitObject.Path.CalculatedDistance) ?? hitObject.Path.CalculatedDistance;
         }
 
         /// <summary>

osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs

@@ -486,7 +486,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
                     Vector2 originalPosition = movementBlueprintOriginalPositions[i];
                     var testPosition = originalPosition + distanceTravelled;
 
-                    var positionalResult = snapProvider.SnapScreenSpacePositionToValidPosition(testPosition);
+                    var positionalResult = snapProvider.FindSnappedPosition(testPosition);
 
                     if (positionalResult.ScreenSpacePosition == testPosition) continue;
 
@@ -505,7 +505,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
             Vector2 movePosition = movementBlueprintOriginalPositions.First() + distanceTravelled;
 
             // Retrieve a snapped position.
-            var result = snapProvider?.SnapScreenSpacePositionToValidTime(movePosition);
+            var result = snapProvider?.FindSnappedPositionAndTime(movePosition);
 
             if (result == null)
             {

osu.Game/Screens/Edit/Compose/Components/CircularDistanceSnapGrid.cs

@@ -80,7 +80,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
             Vector2 normalisedDirection = direction * new Vector2(1f / distance);
             Vector2 snappedPosition = StartPosition + normalisedDirection * radialCount * radius;
 
-            return (snappedPosition, StartTime + SnapProvider.GetSnappedDurationFromDistance(ReferenceObject, (snappedPosition - StartPosition).Length));
+            return (snappedPosition, StartTime + SnapProvider.FindSnappedDuration(ReferenceObject, (snappedPosition - StartPosition).Length));
         }
     }
 }

osu.Game/Screens/Edit/Compose/Components/ComposeBlueprintContainer.cs

@@ -214,7 +214,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
 
         private void updatePlacementPosition()
         {
-            var snapResult = Composer.SnapScreenSpacePositionToValidTime(inputManager.CurrentState.Mouse.Position);
+            var snapResult = Composer.FindSnappedPositionAndTime(inputManager.CurrentState.Mouse.Position);
 
             // if no time was found from positional snapping, we should still quantize to the beat.
             snapResult.Time ??= Beatmap.SnapTime(EditorClock.CurrentTime, null);

osu.Game/Screens/Edit/Compose/Components/Timeline/Timeline.cs

@@ -19,7 +19,6 @@ using osuTK;
 
 namespace osu.Game.Screens.Edit.Compose.Components.Timeline
 {
-    [Cached(typeof(IPositionSnapProvider))]
     [Cached]
     public class Timeline : ZoomableScrollContainer, IPositionSnapProvider
     {
@@ -307,10 +306,10 @@ namespace osu.Game.Screens.Edit.Compose.Components.Timeline
         /// </summary>
         public double VisibleRange => track.Length / Zoom;
 
-        public SnapResult SnapScreenSpacePositionToValidPosition(Vector2 screenSpacePosition) =>
+        public SnapResult FindSnappedPosition(Vector2 screenSpacePosition) =>
             new SnapResult(screenSpacePosition, null);
 
-        public SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition) =>
+        public SnapResult FindSnappedPositionAndTime(Vector2 screenSpacePosition) =>
             new SnapResult(screenSpacePosition, beatSnapProvider.SnapTime(getTimeFromPosition(Content.ToLocalSpace(screenSpacePosition))));
 
         private double getTimeFromPosition(Vector2 localPosition) =>

osu.Game/Screens/Edit/Compose/Components/Timeline/TimelineHitObjectBlueprint.cs

@@ -382,7 +382,7 @@ namespace osu.Game.Screens.Edit.Compose.Components.Timeline
                 {
                     OnDragHandled?.Invoke(e);
 
-                    if (timeline.SnapScreenSpacePositionToValidTime(e.ScreenSpaceMousePosition).Time is double time)
+                    if (timeline.FindSnappedPositionAndTime(e.ScreenSpaceMousePosition).Time is double time)
                     {
                         switch (hitObject)
                         {

osu.Game/Screens/Edit/Compose/IPlacementHandler.cs

@@ -1,10 +1,12 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
 using osu.Game.Rulesets.Objects;
 
 namespace osu.Game.Screens.Edit.Compose
 {
+    [Cached]
     public interface IPlacementHandler
     {
         /// <summary>

osu.Game/Screens/OnlinePlay/FreeModSelectScreen.cs

@@ -16,7 +16,7 @@ namespace osu.Game.Screens.OnlinePlay
         public new Func<Mod, bool> IsValidMod
         {
             get => base.IsValidMod;
-            set => base.IsValidMod = m => m.HasImplementation && m.UserPlayable && value.Invoke(m);
+            set => base.IsValidMod = m => m.UserPlayable && value.Invoke(m);
         }
 
         public FreeModSelectScreen()

osu.Game/Screens/Select/BeatmapCarousel.cs

@@ -604,34 +604,20 @@ namespace osu.Game.Screens.Select
         public void ScrollToSelected(bool immediate = false) =>
             pendingScrollOperation = immediate ? PendingScrollOperation.Immediate : PendingScrollOperation.Standard;
 
-        #region Key / button selection logic
+        #region Button selection logic
-
-        protected override bool OnKeyDown(KeyDownEvent e)
-        {
-            switch (e.Key)
-            {
-                case Key.Left:
-                    SelectNext(-1);
-                    return true;
-
-                case Key.Right:
-                    SelectNext();
-                    return true;
-            }
-
-            return false;
-        }
 
         public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
         {
             switch (e.Action)
             {
                 case GlobalAction.SelectNext:
-                    SelectNext(1, false);
+                case GlobalAction.SelectNextGroup:
+                    SelectNext(1, e.Action == GlobalAction.SelectNextGroup);
                     return true;
 
                 case GlobalAction.SelectPrevious:
-                    SelectNext(-1, false);
+                case GlobalAction.SelectPreviousGroup:
+                    SelectNext(-1, e.Action == GlobalAction.SelectPreviousGroup);
                     return true;
             }
 

osu.Game/Tests/Visual/PlacementBlueprintTestScene.cs

@@ -14,7 +14,6 @@ using osu.Game.Screens.Edit.Compose;
 
 namespace osu.Game.Tests.Visual
 {
-    [Cached(Type = typeof(IPlacementHandler))]
     public abstract class PlacementBlueprintTestScene : OsuManualInputManagerTestScene, IPlacementHandler
     {
         protected readonly Container HitObjectContainer;