diff --git a/BallanceTasEditor/Utils/TasStorage.cs b/BallanceTasEditor/Utils/TasStorage.cs
index be1e7b3..4b07531 100644
--- a/BallanceTasEditor/Utils/TasStorage.cs
+++ b/BallanceTasEditor/Utils/TasStorage.cs
@@ -16,7 +16,7 @@ namespace BallanceTasEditor.Utils {
         /// </summary>
         /// <param name="index">要访问的单元的索引。</param>
         /// <returns>被访问的单元。</returns>
-        /// <exception cref="ArgumentOutOfRangeException">给定的索引超出范围。</exception>
+        /// <exception cref="ArgumentException">给定的索引超出范围。</exception>
         T Visit(int index);
         /// <summary>
         /// 在给定的索引<b>之前</b>插入给定的项目。
@@ -29,14 +29,14 @@ namespace BallanceTasEditor.Utils {
         /// </remarks>
         /// <param name="index">要在前方插入数据的元素的索引。</param>
         /// <param name="items">要插入的元素的迭代器。</param>
-        /// <exception cref="ArgumentOutOfRangeException">给定的索引超出范围。</exception>
+        /// <exception cref="ArgumentException">给定的索引超出范围。</exception>
         void Insert(int index, IEnumerable<T> items);
         /// <summary>
         /// 从给定单元开始，移除给定个数的元素。
         /// </summary>
         /// <param name="index">要开始移除的单元的索引。</param>
         /// <param name="count">要移除的元素的个数。</param>
-        /// <exception cref="ArgumentOutOfRangeException">给定的索引超出范围。</exception>
+        /// <exception cref="ArgumentException">给定的索引超出范围。</exception>
         void Remove(int index, int count);
 
         /// <summary>
@@ -154,7 +154,7 @@ namespace BallanceTasEditor.Utils {
             public int Offset;
 
             public int CompareTo(NodeSeekInfo other) {
-                return this.Offset.CompareTo(other.Offset);
+                return Math.Abs(this.Offset).CompareTo(Math.Abs(other.Offset));
             }
         }
 
@@ -173,8 +173,8 @@ namespace BallanceTasEditor.Utils {
             // 创建三个候选方案。
             var candidates = new NodeSeekInfo[3] {
                 new NodeSeekInfo() { Origin = NodeSeekOrigin.Head, Offset = desiredIndex },
-                new NodeSeekInfo() { Origin = NodeSeekOrigin.Cursor, Offset = desiredIndex - (GetCount() - 1) },
-                new NodeSeekInfo() { Origin = NodeSeekOrigin.Tail, Offset = desiredIndex - m_CursorIndex.Value },
+                new NodeSeekInfo() { Origin = NodeSeekOrigin.Tail, Offset = desiredIndex - (GetCount() - 1) },
+                new NodeSeekInfo() { Origin = NodeSeekOrigin.Cursor, Offset = desiredIndex - m_CursorIndex.Value },
             };
             // 确定哪个候选方案最短。
             var bestCandidate = candidates.Min();
@@ -211,15 +211,25 @@ namespace BallanceTasEditor.Utils {
         }
 
         public T Visit(int index) {
-            MoveToIndex(index);
-            return m_Cursor.Value;
+            if (index < 0 || index >= GetCount()) {
+                throw new ArgumentOutOfRangeException("Index out of range.");
+            } else {
+                MoveToIndex(index);
+                return m_Cursor.Value;
+            }
         }
 
         public void Insert(int index, IEnumerable<T> items) {
-            if (index == GetCount()) {
+            if (index < 0 || index > GetCount()) {
+                throw new ArgumentOutOfRangeException("Index out of range.");
+            } else if (index == GetCount()) {
                 foreach (T item in items) {
                     m_Container.AddLast(item);
                 }
+
+                m_Cursor = m_Container.First;
+                if (m_Cursor is null) m_CursorIndex = null;
+                else m_CursorIndex = 0;
             } else {
                 MoveToIndex(index);
 
@@ -233,7 +243,9 @@ namespace BallanceTasEditor.Utils {
         }
 
         public void Remove(int index, int count) {
-            if (index + count >= GetCount())
+            if (count == 0)
+                return;
+            if (index + count > GetCount())
                 throw new ArgumentOutOfRangeException("Expected removed items out of range.");
 
             MoveToIndex(index);
@@ -253,14 +265,20 @@ namespace BallanceTasEditor.Utils {
             }
 
             // 然后设置Cursor和Index
-            // 如果全部删完了，就清除这两个的设置。
-            // 否则就以prevNode为当前Cursor，Index--为对应Index。
             if (IsEmpty()) {
+                // 如果全部删完了，就清除这两个的设置。
                 m_Cursor = null;
                 m_CursorIndex = null;
             } else {
-                m_Cursor = prevNode;
-                --m_CursorIndex;
+                if (prevNode is null) {
+                    // 如果是按头部删除的，则直接获取头部及其Index。
+                    m_Cursor = m_Container.First;
+                    m_CursorIndex = 0;
+                } else {
+                    // 否则就以prevNode为当前Cursor，Index--为对应Index。
+                    m_Cursor = prevNode;
+                    --m_CursorIndex;
+                }
             }
         }
 
diff --git a/BallanceTasEditorTests/AssertExtension.cs b/BallanceTasEditorTests/AssertExtension.cs
new file mode 100644
index 0000000..ca2e247
--- /dev/null
+++ b/BallanceTasEditorTests/AssertExtension.cs
@@ -0,0 +1,28 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BallanceTasEditorTests {
+    public static class AssertExtension {
+        public static T ThrowsDerivedException<T>(Action action) where T : Exception {
+            try {
+                action();
+            } catch (T ex) {
+                return ex;
+            } catch (Exception ex) {
+                if (ex is T derivedEx)
+                    return derivedEx;
+
+                throw new AssertFailedException(
+                    $"Expected exception of type {typeof(T)} or derived type, but got {ex.GetType()}. " +
+                    $"Message: {ex.Message}");
+            }
+
+            throw new AssertFailedException(
+                $"Expected exception of type {typeof(T)} or derived type, but no exception was thrown.");
+        }
+    }
+}
diff --git a/BallanceTasEditorTests/BallanceTasEditorTests.csproj b/BallanceTasEditorTests/BallanceTasEditorTests.csproj
index 5edd915..97453ba 100644
--- a/BallanceTasEditorTests/BallanceTasEditorTests.csproj
+++ b/BallanceTasEditorTests/BallanceTasEditorTests.csproj
@@ -49,6 +49,7 @@
     <Reference Include="System.Core" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="AssertExtension.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Utils\TasStorageTests.cs" />
   </ItemGroup>
diff --git a/BallanceTasEditorTests/Utils/TasStorageTests.cs b/BallanceTasEditorTests/Utils/TasStorageTests.cs
index 09995e5..2aab09d 100644
--- a/BallanceTasEditorTests/Utils/TasStorageTests.cs
+++ b/BallanceTasEditorTests/Utils/TasStorageTests.cs
@@ -10,6 +10,7 @@ namespace BallanceTasEditorTests.Utils {
     [TestClass]
     public class TasStorageTests {
 
+        private static readonly int[] BLANK = { };
         private static readonly int[] PROBE = { 10, 20, 30, 40, 50 };
 
         private static IEnumerable<object[]> TasStorageInstanceProvider {
@@ -28,18 +29,18 @@ namespace BallanceTasEditorTests.Utils {
         [DynamicData(nameof(TasStorageInstanceProvider))]
         public void VisitTest(ITasStorage<int> storage) {
             // 空时访问
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Visit(-1));
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Visit(0));
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Visit(1));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(-1));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(0));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(1));
 
             // 设置数据
             storage.Insert(0, PROBE);
             // 访问数据
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Visit(-1));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(-1));
             for (int i = 0; i < PROBE.Length; i++) {
                 Assert.AreEqual(storage.Visit(i), PROBE[i]);
             }
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Visit(PROBE.Length));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(PROBE.Length));
         }
 
         /// <summary>
@@ -52,8 +53,8 @@ namespace BallanceTasEditorTests.Utils {
             // 和在非空时的头，中，尾分别插入的结果。
 
             // 先检测空插入
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Insert(-1, PROBE));
-            Assert.ThrowsException<ArgumentOutOfRangeException>(() => storage.Insert(1, PROBE));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Insert(-1, PROBE));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Insert(1, PROBE));
             storage.Insert(0, PROBE);
             for (int i = 0; i < PROBE.Length; i++) {
                 Assert.AreEqual(storage.Visit(i), PROBE[i]);
@@ -78,6 +79,7 @@ namespace BallanceTasEditorTests.Utils {
                     Assert.AreEqual(storage.Visit(i), expected[i]);
                 }
             }
+
         }
 
         /// <summary>
@@ -86,7 +88,28 @@ namespace BallanceTasEditorTests.Utils {
         [TestMethod]
         [DynamicData(nameof(TasStorageInstanceProvider))]
         public void RemoveTest(ITasStorage<int> storage) {
+            // 在空的时候删除0项
+            storage.Remove(0, 0);
 
+            // 插入项目后尝试在头中尾分别删除
+            var indices = new int[] { 0, PROBE.Length / 2, PROBE.Length - 1 };
+            foreach (var index in indices) {
+                // 清空，插入，删除
+                storage.Clear();
+                storage.Insert(0, PROBE);
+                storage.Remove(index, 1);
+
+                // 用List做正确模拟
+                var expected = new List<int>();
+                expected.AddRange(PROBE);
+                expected.RemoveRange(index, 1);
+
+                // 检查结果
+                Assert.AreEqual(storage.GetCount(), expected.Count);
+                for (int i = 0; i < expected.Count; i++) {
+                    Assert.AreEqual(storage.Visit(i), expected[i]);
+                }
+            }
         }
 
         /// <summary>
@@ -159,6 +182,13 @@ namespace BallanceTasEditorTests.Utils {
             // 再次检查数据
             Assert.IsTrue(storage.IsEmpty());
             Assert.AreEqual(storage.GetCount(), 0);
+
+            // 清空后插入0项，然后确认
+            storage.Clear();
+            storage.Insert(0, BLANK);
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(-1));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(0));
+            AssertExtension.ThrowsDerivedException<ArgumentException>(() => storage.Visit(1));
         }
     }
 }