diff --git a/Ink Canvas/MainWindow.xaml b/Ink Canvas/MainWindow.xaml
index 53bf343..acf6c19 100644
--- a/Ink Canvas/MainWindow.xaml	
+++ b/Ink Canvas/MainWindow.xaml	
@@ -20,7 +20,7 @@
         Closing="Window_Closing"
         Closed="Window_Closed"
         PreviewKeyDown="Main_Grid_PreviewKeyDown"
-        Height="1000" Width="1000"
+        Height="10000" Width="1000"
         FontFamily="Microsoft YaHei UI"
         MouseWheel="Window_MouseWheel"
         Foreground="Black"
@@ -424,6 +424,12 @@
                                 </ComboBox>
                                 <ui:ToggleSwitch Name="ToggleSwitchHideStrokeWhenSelecting" Header="切换到鼠标模式后隐藏墨迹" IsOn="False" FontFamily="Microsoft YaHei UI" OnContent="开" OffContent="关" Toggled="ToggleSwitchHideStrokeWhenSelecting_Toggled"/>
                                 <ui:ToggleSwitch Name="ToggleSwitchUsingWhiteboard" Header="使用白板 (白色背景)" IsOn="False" FontFamily="Microsoft YaHei UI" OnContent="开" OffContent="关" Toggled="ToggleSwitchUsingWhiteboard_Toggled"/>
+                                <TextBlock Text="保留双曲线渐近线" FontFamily="Microsoft YaHei UI" FontSize="14"/>
+                                <ComboBox Name="ComboBoxHyperbolaAsymptoteOption" FontFamily="Microsoft YaHei UI" SelectedIndex="2" SelectionChanged="ComboBoxHyperbolaAsymptoteOption_SelectionChanged">
+                                    <ComboBoxItem Content="是" FontFamily="Microsoft YaHei UI"/>
+                                    <ComboBoxItem Content="否" FontFamily="Microsoft YaHei UI"/>
+                                    <ComboBoxItem Content="每次询问" FontFamily="Microsoft YaHei UI"/>
+                                </ComboBox>
                             </ui:SimpleStackPanel>
                         </GroupBox>
                         <GroupBox Header="手势">
diff --git a/Ink Canvas/MainWindow.xaml.cs b/Ink Canvas/MainWindow.xaml.cs
index 55afe7c..3687af1 100644
--- a/Ink Canvas/MainWindow.xaml.cs	
+++ b/Ink Canvas/MainWindow.xaml.cs	
@@ -2915,6 +2915,13 @@ namespace Ink_Canvas
             SaveSettingsToFile();
         }
 
+        private void ComboBoxHyperbolaAsymptoteOption_SelectionChanged(object sender, SelectionChangedEventArgs e)
+        {
+            if (!isLoaded) return;
+            Settings.Canvas.HyperbolaAsymptoteOption = (OptionalOperation)ComboBoxEraserSize.SelectedIndex;
+            SaveSettingsToFile();
+        }
+
         #endregion
 
         #region Automation
@@ -5352,11 +5359,26 @@ namespace Ink_Canvas
                 else
                 {
                     drawMultiStepShapeCurrentStep = 0;
-                    try
+                    if (drawMultiStepShapeSpecialStrokeCollection != null)
                     {
-                        inkCanvas.Strokes.Remove(drawMultiStepShapeSpecialStrokeCollection);
+                        bool opFlag = false;
+                        switch (Settings.Canvas.HyperbolaAsymptoteOption)
+                        {
+                            case OptionalOperation.Yes:
+                                opFlag = true;
+                                break;
+                            case OptionalOperation.No:
+                                opFlag = false;
+                                break;
+                            case OptionalOperation.Ask:
+                                opFlag = MessageBox.Show("是否移除渐近线？", "Ink Canvas", MessageBoxButton.YesNo) != MessageBoxResult.Yes;
+                                break;
+                        };
+                        if (!opFlag)
+                        {
+                            inkCanvas.Strokes.Remove(drawMultiStepShapeSpecialStrokeCollection);
+                        }
                     }
-                    catch { }
                     BtnPen_Click(null, null); //画完还原到笔模式
                 }
             }
diff --git a/Ink Canvas/Settings.cs b/Ink Canvas/Settings.cs
index fede77b..4739685 100644
--- a/Ink Canvas/Settings.cs	
+++ b/Ink Canvas/Settings.cs	
@@ -38,6 +38,16 @@ namespace Ink_Canvas
 
         [JsonProperty("usingWhiteboard")]
         public bool UsingWhiteboard { get; set; }
+
+        [JsonProperty("hyperbolaAsymptoteOption")]
+        public OptionalOperation HyperbolaAsymptoteOption { get; set; } = OptionalOperation.Ask;
+    }
+
+    public enum OptionalOperation
+    {
+        Yes,
+        No,
+        Ask
     }
 
     public class Gesture