diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/ConnectionViewModel.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/ConnectionViewModel.cs
index 30cdb60..0b992a1 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/ConnectionViewModel.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/ConnectionViewModel.cs
@@ -702,7 +702,7 @@ namespace AIStudio.Wpf.DiagramDesigner
             {
                 IsInternalChanged = true;
                 startVertice.SetPosition(StartPoint);
-                IsInternalChanged = true;
+                IsInternalChanged = false;
             }
             startVertice.ColorViewModel.FillColor.Color = SourceConnectorInfoFully != null ? Colors.DarkRed : Colors.Blue;
             startVertice.ColorViewModel.LineColor.Color = SourceConnectorInfoFully != null ? Colors.DarkRed : Colors.Blue;
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs
index f8fa8ad..b4c30b3 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs
@@ -536,6 +536,7 @@ namespace AIStudio.Wpf.DiagramDesigner
 
         public virtual void Dispose()
         {
+            this.PropertyChanged -= Item_PropertyChanged;
         }
     }
 }