diff --git a/osu.Game.Rulesets.Karaoke.Tests/Editor/ChangeHandlers/Stages/StageElementCategoryChangeHandlerTest.cs b/osu.Game.Rulesets.Karaoke.Tests/Editor/ChangeHandlers/Stages/StageElementCategoryChangeHandlerTest.cs
index 9089a0b91..804b85012 100644
--- a/osu.Game.Rulesets.Karaoke.Tests/Editor/ChangeHandlers/Stages/StageElementCategoryChangeHandlerTest.cs
+++ b/osu.Game.Rulesets.Karaoke.Tests/Editor/ChangeHandlers/Stages/StageElementCategoryChangeHandlerTest.cs
@@ -119,49 +119,6 @@ public void TestAddToMapping()
         });
     }
 
-    [Test]
-    public void TestOffsetMapping()
-    {
-        Lyric lyric = new Lyric();
-        Lyric unSelectedLyric = new Lyric();
-
-        SetUpStageInfo<TestStageInfo>(stageInfo =>
-        {
-            var category = stageInfo.Category;
-            var element = category.AddElement(x => x.Name = "Element 1");
-            category.AddElement(x => x.Name = "Element 2");
-
-            // Add to Mapping
-            category.AddToMapping(element, lyric);
-            category.AddToMapping(element, unSelectedLyric);
-        });
-
-        PrepareHitObject(() => lyric);
-        PrepareHitObject(() => unSelectedLyric, false);
-
-        TriggerHandlerChanged(c =>
-        {
-            c.OffsetMapping(1);
-        });
-
-        AssertStageInfo<TestStageInfo>(stageInfo =>
-        {
-            var category = stageInfo.Category;
-
-            Assert.AreEqual("Element 2", category.GetElementByItem(lyric).Name);
-            Assert.AreEqual("Element 1", category.GetElementByItem(unSelectedLyric).Name); // should not change the id if lyric is not selected.
-        });
-    }
-
-    [Test]
-    public void TestOffsetMappingWithZeroValue()
-    {
-        PrepareHitObject(() => new Lyric());
-
-        // offset value should not be zero.
-        TriggerHandlerChangedWithException<InvalidOperationException>(c => c.OffsetMapping(0));
-    }
-
     [Test]
     public void TestRemoveFromMapping()
     {
diff --git a/osu.Game.Rulesets.Karaoke.Tests/Editor/Generator/Stages/BaseStageElementCategoryGeneratorTest.cs b/osu.Game.Rulesets.Karaoke.Tests/Editor/Generator/Stages/BaseStageElementCategoryGeneratorTest.cs
index e147cd415..d3b017f5f 100644
--- a/osu.Game.Rulesets.Karaoke.Tests/Editor/Generator/Stages/BaseStageElementCategoryGeneratorTest.cs
+++ b/osu.Game.Rulesets.Karaoke.Tests/Editor/Generator/Stages/BaseStageElementCategoryGeneratorTest.cs
@@ -15,14 +15,14 @@ public abstract class BaseLyricStageElementCategoryGeneratorTest<TGenerator, TOb
     : BaseStageElementCategoryGeneratorTest<TGenerator, TObject, TStageElement, Lyric, TConfig>
     where TGenerator : StageInfoPropertyGenerator<TObject, TConfig>
     where TObject : StageElementCategory<TStageElement, Lyric>
-    where TStageElement : StageElement, IComparable<TStageElement>, new()
+    where TStageElement : StageElement, new()
     where TConfig : GeneratorConfig, new();
 
 public abstract class BaseStageElementCategoryGeneratorTest<TGenerator, TObject, TStageElement, THitObject, TConfig>
     : BaseStageInfoPropertyGeneratorTest<TGenerator, TObject, TConfig>
     where TGenerator : StageInfoPropertyGenerator<TObject, TConfig>
     where TObject : StageElementCategory<TStageElement, THitObject>
-    where TStageElement : StageElement, IComparable<TStageElement>, new()
+    where TStageElement : StageElement, new()
     where THitObject : KaraokeHitObject, IHasPrimaryKey
     where TConfig : GeneratorConfig, new()
 {
diff --git a/osu.Game.Rulesets.Karaoke.Tests/Stages/Infos/StageElementCategoryTest.cs b/osu.Game.Rulesets.Karaoke.Tests/Stages/Infos/StageElementCategoryTest.cs
index 619b564dc..9d47b6937 100644
--- a/osu.Game.Rulesets.Karaoke.Tests/Stages/Infos/StageElementCategoryTest.cs
+++ b/osu.Game.Rulesets.Karaoke.Tests/Stages/Infos/StageElementCategoryTest.cs
@@ -226,20 +226,6 @@ public void TestGetHitObjectIdsByElement()
         Assert.IsEmpty(category.GetHitObjectIdsByElement(defaultElement));
     }
 
-    [Test]
-    public void TestGetElementOrder()
-    {
-        var category = new TestStageElementCategory();
-        var element = category.AddElement();
-
-        int? existElementOrder = category.GetElementOrder(element);
-        Assert.AreEqual(1, existElementOrder);
-
-        var notExistElement = new TestStageElement();
-        int? notExistElementOrder = category.GetElementOrder(notExistElement);
-        Assert.IsNull(notExistElementOrder);
-    }
-
     #endregion
 
     private class TestStageElement : StageElement, IComparable<TestStageElement>
diff --git a/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/IStageElementCategoryChangeHandler.cs b/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/IStageElementCategoryChangeHandler.cs
index 77a84c4ed..237909497 100644
--- a/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/IStageElementCategoryChangeHandler.cs
+++ b/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/IStageElementCategoryChangeHandler.cs
@@ -18,8 +18,6 @@ public interface IStageElementCategoryChangeHandler<TStageElement>
 
     void AddToMapping(TStageElement element);
 
-    void OffsetMapping(int offset);
-
     void RemoveFromMapping();
 
     void ClearUnusedMapping();
diff --git a/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/StageElementCategoryChangeHandler.cs b/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/StageElementCategoryChangeHandler.cs
index 03d1bbb3a..d86614b3f 100644
--- a/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/StageElementCategoryChangeHandler.cs
+++ b/osu.Game.Rulesets.Karaoke/Edit/ChangeHandlers/Stages/StageElementCategoryChangeHandler.cs
@@ -56,31 +56,6 @@ public void AddToMapping(TStageElement element)
         });
     }
 
-    public void OffsetMapping(int offset)
-    {
-        if (offset == 0)
-            throw new InvalidOperationException("Offset number should not be zero.");
-
-        PerformOnSelection<THitObject>(hitObject =>
-        {
-            performStageInfoChanged(s =>
-            {
-                var element = s.GetElementByItem(hitObject);
-                int mappingIndex = s.SortedElements.IndexOf(element);
-                if (mappingIndex < 0)
-                    return;
-
-                int newMappingIndex = mappingIndex + offset;
-                var newElement = s.SortedElements.ElementAtOrDefault(newMappingIndex);
-                if (newElement == null)
-                    return;
-
-                s.RemoveHitObjectFromMapping(hitObject);
-                s.AddToMapping(newElement, hitObject);
-            });
-        });
-    }
-
     public void RemoveFromMapping()
     {
         PerformOnSelection<THitObject>(hitObject =>
diff --git a/osu.Game.Rulesets.Karaoke/Edit/Checks/CheckStageInfo.cs b/osu.Game.Rulesets.Karaoke/Edit/Checks/CheckStageInfo.cs
index 3123c228a..18ee2a131 100644
--- a/osu.Game.Rulesets.Karaoke/Edit/Checks/CheckStageInfo.cs
+++ b/osu.Game.Rulesets.Karaoke/Edit/Checks/CheckStageInfo.cs
@@ -34,7 +34,7 @@ private readonly IList<Func<TStageInfo, IReadOnlyList<KaraokeHitObject>, IEnumer
         = new List<Func<TStageInfo, IReadOnlyList<KaraokeHitObject>, IEnumerable<Issue>>>();
 
     public void RegisterCategory<TStageElement, THitObject>(Func<TStageInfo, StageElementCategory<TStageElement, THitObject>> categoryAction, int minimumRequiredElements)
-        where TStageElement : StageElement, IComparable<TStageElement>, new()
+        where TStageElement : StageElement, new()
         where THitObject : KaraokeHitObject, IHasPrimaryKey
     {
         stageInfoCategoryActions.Add((info, hitObjects) =>
@@ -46,7 +46,7 @@ public void RegisterCategory<TStageElement, THitObject>(Func<TStageInfo, StageEl
 
     private IEnumerable<Issue> checkElementCategory<TStageElement, THitObject>(StageElementCategory<TStageElement, THitObject> category, IReadOnlyList<THitObject> hitObjects,
                                                                                int minimumRequiredElements)
-        where TStageElement : StageElement, IComparable<TStageElement>, new()
+        where TStageElement : StageElement, new()
         where THitObject : KaraokeHitObject, IHasPrimaryKey
     {
         // check mapping.
@@ -68,7 +68,7 @@ private IEnumerable<Issue> checkElementCategory<TStageElement, THitObject>(Stage
     }
 
     private IEnumerable<Issue> checkMappings<TStageElement, THitObject>(StageElementCategory<TStageElement, THitObject> category, IReadOnlyList<THitObject> hitObjects)
-        where TStageElement : StageElement, IComparable<TStageElement>, new()
+        where TStageElement : StageElement, new()
         where THitObject : KaraokeHitObject, IHasPrimaryKey
     {
         var elements = category.AvailableElements;
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicLyricLayout.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicLyricLayout.cs
index df524fee0..d8680c3b4 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicLyricLayout.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicLyricLayout.cs
@@ -1,15 +1,13 @@
 // Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using Newtonsoft.Json;
 using osu.Framework.Bindables;
 using osu.Game.Rulesets.Karaoke.Objects;
-using osu.Game.Rulesets.Karaoke.Utils;
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Infos.Classic;
 
-public class ClassicLyricLayout : StageElement, IComparable<ClassicLyricLayout>
+public class ClassicLyricLayout : StageElement
 {
     [JsonIgnore]
     public readonly Bindable<ClassicLyricLayoutAlignment> AlignmentBindable = new(ClassicLyricLayoutAlignment.Center);
@@ -20,11 +18,7 @@ public class ClassicLyricLayout : StageElement, IComparable<ClassicLyricLayout>
     public ClassicLyricLayoutAlignment Alignment
     {
         get => AlignmentBindable.Value;
-        set
-        {
-            AlignmentBindable.Value = value;
-            TriggerOrderVersionChanged();
-        }
+        set => AlignmentBindable.Value = value;
     }
 
     [JsonIgnore]
@@ -36,11 +30,7 @@ public ClassicLyricLayoutAlignment Alignment
     public float HorizontalMargin
     {
         get => HorizontalMarginBindable.Value;
-        set
-        {
-            HorizontalMarginBindable.Value = value;
-            TriggerOrderVersionChanged();
-        }
+        set => HorizontalMarginBindable.Value = value;
     }
 
     [JsonIgnore]
@@ -53,19 +43,6 @@ public float HorizontalMargin
     public int Line
     {
         get => LineBindable.Value;
-        set
-        {
-            LineBindable.Value = value;
-            TriggerOrderVersionChanged();
-        }
-    }
-
-    public int CompareTo(ClassicLyricLayout? other)
-    {
-        return ComparableUtils.CompareByProperty(this, other,
-            x => x.Line,
-            x => x.Alignment,
-            x => x.HorizontalMargin,
-            x => x.ID);
+        set => LineBindable.Value = value;
     }
 }
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStageInfo.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStageInfo.cs
index 54792e624..5eb93de3b 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStageInfo.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStageInfo.cs
@@ -11,17 +11,17 @@ public class ClassicStageInfo : StageInfo
 {
     #region Category
 
-    /// <summary>
-    /// Category to save the <see cref="Lyric"/>'s and <see cref="Note"/>'s style.
-    /// </summary>
-    public ClassicStyleCategory StyleCategory { get; set; } = new();
-
     /// <summary>
     /// The definition for the <see cref="Lyric"/>.<br/>
     /// Like the line height or font size.
     /// </summary>
     public ClassicStageDefinition StageDefinition { get; set; } = new();
 
+    /// <summary>
+    /// Category to save the <see cref="Lyric"/>'s and <see cref="Note"/>'s style.
+    /// </summary>
+    public ClassicStyleCategory StyleCategory { get; set; } = new();
+
     /// <summary>
     /// Category to save the <see cref="Lyric"/>'s layout.
     /// </summary>
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStyle.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStyle.cs
index 76b36789d..51c54f8cd 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStyle.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Classic/ClassicStyle.cs
@@ -9,7 +9,7 @@
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Infos.Classic;
 
-public class ClassicStyle : StageElement, IComparable<ClassicStyle>
+public class ClassicStyle : StageElement
 {
     [JsonIgnore]
     public readonly Bindable<int?> LyricStyleIndexBindable = new();
@@ -34,11 +34,4 @@ public int? NoteStyleIndex
         get => NoteStyleIndexBindable.Value;
         set => NoteStyleIndexBindable.Value = value;
     }
-
-    public int CompareTo(ClassicStyle? other)
-    {
-        return ComparableUtils.CompareByProperty(this, other,
-            x => x.Name,
-            x => x.ID);
-    }
 }
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewLyricLayout.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewLyricLayout.cs
index b36ae19aa..fbf9b51ab 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewLyricLayout.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewLyricLayout.cs
@@ -1,14 +1,12 @@
 // Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using System.Collections.Generic;
 using osu.Game.Rulesets.Karaoke.Objects;
-using osu.Game.Rulesets.Karaoke.Utils;
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Infos.Preview;
 
-public class PreviewLyricLayout : StageElement, IComparable<PreviewLyricLayout>
+public class PreviewLyricLayout : StageElement
 {
     /// <summary>
     /// <see cref="Lyric"/>'s timing with row index.
@@ -24,10 +22,4 @@ public class PreviewLyricLayout : StageElement, IComparable<PreviewLyricLayout>
     /// <see cref="Lyric"/>'s end time.
     /// </summary>
     public double EndTime { get; set; }
-
-    public int CompareTo(PreviewLyricLayout? other)
-    {
-        return ComparableUtils.CompareByProperty(this, other,
-            x => x.ID);
-    }
 }
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStageInfo.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStageInfo.cs
index 1b81a3080..ebe693113 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStageInfo.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStageInfo.cs
@@ -16,20 +16,22 @@ public class PreviewStageInfo : StageInfo, IHasCalculatedProperty
 {
     #region Category
 
-    /// <summary>
-    /// Category to save the <see cref="Lyric"/>'s and <see cref="Note"/>'s style.
-    /// </summary>
-    [JsonIgnore]
-    private PreviewStyleCategory styleCategory { get; set; } = new();
-
     /// <summary>
     /// The definition for the <see cref="Lyric"/>.
     /// Like how many lyrics can in the playfield at the same time.
     /// </summary>
     public PreviewStageDefinition StageDefinition { get; set; } = new();
 
+    /// <summary>
+    /// Category to save the <see cref="Lyric"/>'s and <see cref="Note"/>'s style.
+    /// This property will not be saved because it's real-time calculated.
+    /// </summary>
+    [JsonIgnore]
+    private PreviewStyleCategory styleCategory { get; set; } = new();
+
     /// <summary>
     /// Category to save the <see cref="Lyric"/>'s layout.
+    /// This property will not be saved because it's real-time calculated.
     /// </summary>
     [JsonIgnore]
     private PreviewLyricLayoutCategory layoutCategory { get; set; } = new();
@@ -38,32 +40,12 @@ public class PreviewStageInfo : StageInfo, IHasCalculatedProperty
 
     #region Validation
 
-    private bool calculatedPropertyIsUpdated;
-
-    /// <summary>
-    /// Mark the stage info's calculated property as invalidate.
-    /// </summary>
-    /// <returns></returns>
-    public void TriggerRecalculate()
-    {
-        calculatedPropertyIsUpdated = false;
-    }
-
-    /// <summary>
-    /// Check if the stage info's calculated property is calculated and the value is the latest.
-    /// </summary>
-    /// <returns></returns>
-    public bool IsUpdated() => calculatedPropertyIsUpdated;
-
     /// <summary>
     /// If the calculated property is not updated, then re-calculate the property inside the stage info in the <see cref="KaraokeBeatmapProcessor"/>
     /// </summary>
     /// <param name="beatmap"></param>
     public void ValidateCalculatedProperty(IBeatmap beatmap)
     {
-        if (IsUpdated())
-            return;
-
         var calculator = new PreviewStageTimingCalculator(beatmap, StageDefinition);
 
         // also, clear all mapping in the layout and re-create one.
@@ -83,8 +65,6 @@ public void ValidateCalculatedProperty(IBeatmap beatmap)
             });
             layoutCategory.AddToMapping(element, lyric);
         }
-
-        calculatedPropertyIsUpdated = true;
     }
 
     #endregion
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStyle.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStyle.cs
index dcf598bbf..9551edd61 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStyle.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Preview/PreviewStyle.cs
@@ -1,13 +1,11 @@
 // Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using osu.Game.Rulesets.Karaoke.Objects;
-using osu.Game.Rulesets.Karaoke.Utils;
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Infos.Preview;
 
-public class PreviewStyle : StageElement, IComparable<PreviewStyle>
+public class PreviewStyle : StageElement
 {
     /// <summary>
     /// <see cref="Lyric"/>'s skin lookup index.
@@ -18,11 +16,4 @@ public class PreviewStyle : StageElement, IComparable<PreviewStyle>
     /// <see cref="Note"/>'s skin lookup index.
     /// </summary>
     public int? NoteStyleIndex { get; set; }
-
-    public int CompareTo(PreviewStyle? other)
-    {
-        return ComparableUtils.CompareByProperty(this, other,
-            x => x.Name,
-            x => x.ID);
-    }
 }
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElement.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElement.cs
index 0295e75d8..c2fc7682c 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElement.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElement.cs
@@ -9,10 +9,6 @@ namespace osu.Game.Rulesets.Karaoke.Stages.Infos;
 
 public abstract class StageElement : IHasPrimaryKey
 {
-    private readonly Bindable<int> orderVersion = new();
-
-    public IBindable<int> OrderVersion => orderVersion;
-
     /// <summary>
     /// Index of the element.
     /// </summary>
@@ -30,9 +26,4 @@ public string Name
         get => NameBindable.Value;
         set => NameBindable.Value = value;
     }
-
-    protected void TriggerOrderVersionChanged()
-    {
-        orderVersion.Value++;
-    }
 }
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElementCategory.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElementCategory.cs
index ea38c583e..7283fdcb0 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElementCategory.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/StageElementCategory.cs
@@ -3,10 +3,7 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Specialized;
-using System.Diagnostics;
 using System.Linq;
-using Newtonsoft.Json;
 using osu.Framework.Bindables;
 using osu.Game.Rulesets.Karaoke.Beatmaps;
 using osu.Game.Rulesets.Karaoke.Objects;
@@ -14,10 +11,11 @@
 namespace osu.Game.Rulesets.Karaoke.Stages.Infos;
 
 /// <summary>
-/// It's a category to record the list of <typeparamref name="TStageElement"/> and handle the mapping by several rules.
+/// It's a category to record the list of <typeparamref name="TStageElement"/> and handle the mapping by default role.<br/>
+/// Can add more customised role by inherit this class.<br/>
 /// </summary>
 public abstract class StageElementCategory<TStageElement, THitObject>
-    where TStageElement : StageElement, IComparable<TStageElement>, new()
+    where TStageElement : StageElement, new()
     where THitObject : KaraokeHitObject, IHasPrimaryKey
 {
     /// <summary>
@@ -26,19 +24,11 @@ public abstract class StageElementCategory<TStageElement, THitObject>
     /// </summary>
     public TStageElement DefaultElement { get; protected set; }
 
-    [JsonIgnore]
-    public IBindable<int> ElementsVersion => elementsVersion;
-
-    private readonly Bindable<int> elementsVersion = new();
-
     /// <summary>
     /// All available elements.
     /// </summary>
     public BindableList<TStageElement> AvailableElements { get; protected set; } = new();
 
-    [JsonIgnore]
-    public List<TStageElement> SortedElements { get; private set; } = new();
-
     /// <summary>
     /// Mapping between <typeparamref name="THitObject.ID"/> and <typeparamref name="TStageElement.ID"/><br/>
     /// This is the 1st mapping roles.
@@ -48,37 +38,6 @@ public abstract class StageElementCategory<TStageElement, THitObject>
     protected StageElementCategory()
     {
         DefaultElement = new TStageElement();
-
-        AvailableElements.CollectionChanged += (_, args) =>
-        {
-            switch (args.Action)
-            {
-                case NotifyCollectionChangedAction.Add:
-                    Debug.Assert(args.NewItems != null);
-
-                    foreach (var c in args.NewItems.Cast<TStageElement>())
-                        c.OrderVersion.ValueChanged += orderValueChanged;
-                    break;
-
-                case NotifyCollectionChangedAction.Reset:
-                case NotifyCollectionChangedAction.Remove:
-                    Debug.Assert(args.OldItems != null);
-
-                    foreach (var c in args.OldItems.Cast<TStageElement>())
-                        c.OrderVersion.ValueChanged -= orderValueChanged;
-                    break;
-            }
-
-            onElementOrderChanged();
-
-            void orderValueChanged(ValueChangedEvent<int> e) => onElementOrderChanged();
-        };
-
-        void onElementOrderChanged()
-        {
-            SortedElements = AvailableElements.OrderBy(x => x).ToList();
-            elementsVersion.Value++;
-        }
     }
 
     #region Edit
@@ -111,13 +70,13 @@ public void RemoveElement(TStageElement element)
         AvailableElements.Remove(element);
     }
 
-    public void ClearElements()
+    public virtual void ClearElements()
     {
         Mappings.Clear();
         AvailableElements.Clear();
     }
 
-    public void AddToMapping(TStageElement element, THitObject hitObject)
+    public virtual void AddToMapping(TStageElement element, THitObject hitObject)
     {
         var key = hitObject.ID;
         var value = element.ID;
@@ -134,12 +93,12 @@ public void AddToMapping(TStageElement element, THitObject hitObject)
         }
     }
 
-    public void RemoveHitObjectFromMapping(THitObject hitObject)
+    public virtual void RemoveHitObjectFromMapping(THitObject hitObject)
     {
         Mappings.Remove(hitObject.ID);
     }
 
-    public void RemoveElementFromMapping(TStageElement element)
+    public virtual void RemoveElementFromMapping(TStageElement element)
     {
         var objectIds = getMappingHitObjectIds(element);
 
@@ -152,7 +111,7 @@ IEnumerable<ElementId> getMappingHitObjectIds(TStageElement stageElement)
             => Mappings.Where(x => x.Value == stageElement.ID).Select(x => x.Key).ToArray();
     }
 
-    public void ClearUnusedMapping(Func<ElementId, bool> checkExist)
+    public virtual void ClearUnusedMapping(Func<ElementId, bool> checkExist)
     {
         var unusedIds = Mappings.Select(x => x.Key).Where(x => !checkExist(x));
 
@@ -166,7 +125,7 @@ public void ClearUnusedMapping(Func<ElementId, bool> checkExist)
 
     #region Query
 
-    public TStageElement GetElementByItem(THitObject hitObject)
+    public virtual TStageElement GetElementByItem(THitObject hitObject)
     {
         var id = hitObject.ID;
 
@@ -177,16 +136,10 @@ public TStageElement GetElementByItem(THitObject hitObject)
         return matchedElements ?? DefaultElement;
     }
 
-    public IEnumerable<ElementId> GetHitObjectIdsByElement(TStageElement element)
+    public virtual IEnumerable<ElementId> GetHitObjectIdsByElement(TStageElement element)
     {
         return Mappings.Where(x => x.Value == element.ID).Select(x => x.Key);
     }
 
-    public int? GetElementOrder(TStageElement element)
-    {
-        int index = SortedElements.IndexOf(element);
-        return index == -1 ? null : index + 1;
-    }
-
     #endregion
 }
diff --git a/osu.Game.Rulesets.Karaoke/Stages/Infos/Types/IHasCalculatedProperty.cs b/osu.Game.Rulesets.Karaoke/Stages/Infos/Types/IHasCalculatedProperty.cs
index cf0160edf..81f43ccce 100644
--- a/osu.Game.Rulesets.Karaoke/Stages/Infos/Types/IHasCalculatedProperty.cs
+++ b/osu.Game.Rulesets.Karaoke/Stages/Infos/Types/IHasCalculatedProperty.cs
@@ -8,18 +8,6 @@ namespace osu.Game.Rulesets.Karaoke.Stages.Infos.Types;
 
 public interface IHasCalculatedProperty
 {
-    /// <summary>
-    /// Mark the stage info's calculated property as invalidate.
-    /// </summary>
-    /// <returns></returns>
-    void TriggerRecalculate();
-
-    /// <summary>
-    /// Check if the stage info's calculated property is calculated and the value is the latest.
-    /// </summary>
-    /// <returns></returns>
-    bool IsUpdated();
-
     /// <summary>
     /// If the calculated property is not updated, then re-calculate the property inside the stage info in the <see cref="KaraokeBeatmapProcessor"/>
     /// </summary>