diff --git a/AIStudio.Wpf.DiagramDesigner/Controls/BlockDragThumb.cs b/AIStudio.Wpf.DiagramDesigner/Controls/BlockDragThumb.cs
index 56b1385..2ce2415 100644
--- a/AIStudio.Wpf.DiagramDesigner/Controls/BlockDragThumb.cs
+++ b/AIStudio.Wpf.DiagramDesigner/Controls/BlockDragThumb.cs
@@ -28,7 +28,7 @@ namespace AIStudio.Wpf.DiagramDesigner.Controls
             if (e.LeftButton == MouseButtonState.Pressed &&  firstPoint == null)
             {
                 firstPoint = e.GetPosition(this);
-                DesignerItem.BeforeExecute();
+                DesignerItem.BeforeExecution();
             }
         }
 
diff --git a/AIStudio.Wpf.DiagramDesigner/Helpers/DrawingHelper.cs b/AIStudio.Wpf.DiagramDesigner/Helpers/DrawingHelper.cs
index c3aa727..f0e5fa0 100644
--- a/AIStudio.Wpf.DiagramDesigner/Helpers/DrawingHelper.cs
+++ b/AIStudio.Wpf.DiagramDesigner/Helpers/DrawingHelper.cs
@@ -84,7 +84,7 @@ namespace AIStudio.Wpf.DiagramDesigner
 
         }
 
-        static double ConvertToPositive360(double angle)
+        public static double ConvertToPositive360(double angle)
         {
             double positiveAngle = angle % 360;
             if (positiveAngle < 0)
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/Container/BlockItemsContainerInfo.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/Container/BlockItemsContainerInfo.cs
index df46c43..a704de7 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/Container/BlockItemsContainerInfo.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/Container/BlockItemsContainerInfo.cs
@@ -70,7 +70,7 @@ namespace AIStudio.Wpf.DiagramDesigner
                     foreach (var child in designer.Children)
                     {
                         BlockDesignerItemViewModel fullyCreatedConnectorInfo = new BlockDesignerItemViewModel(this.Root, child);
-                        InsertChild(fullyCreatedConnectorInfo);
+                        InsertChild(fullyCreatedConnectorInfo, -1);
                     }
                 }
             }
@@ -273,16 +273,17 @@ namespace AIStudio.Wpf.DiagramDesigner
             return double.IsNaN(ItemHeight) ? ActualItemHeight : ItemHeight;
         }
 
-        public void InsertChild(BlockDesignerItemViewModel child)
-        {
-            child.ParentContainer = this;
-            Children.Add(child);
-        }
-
         public void InsertChild(BlockDesignerItemViewModel child, int index)
         {
             child.ParentContainer = this;
-            Children.Insert(index, child);
+            if (index == -1)
+            {
+                Children.Add(child);
+            }
+            else
+            {
+                Children.Insert(index, child);
+            }
         }
 
         public void RemoveChild(BlockDesignerItemViewModel child)
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramViewModel.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramViewModel.cs
index cd4cfb4..ffd3d5d 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramViewModel.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramViewModel.cs
@@ -392,15 +392,6 @@ namespace AIStudio.Wpf.DiagramDesigner
             }
         }
 
-        private ICommand _nextCommand;
-        public ICommand NextCommand
-        {
-            get
-            {
-                return this._nextCommand ?? (this._nextCommand = new SimpleCommand(ExecuteEnable, ExecuteNextCommand));
-            }
-        }
-
         private ICommand _alignTopCommand;
         public ICommand AlignTopCommand
         {
@@ -1067,10 +1058,10 @@ namespace AIStudio.Wpf.DiagramDesigner
             }
         }
 
-        public virtual void ExecuteNextCommand(object parameter)
+        public virtual bool Next()
         {
-
-        }
+            return false;
+        }                 
 
         private void ExecuteSelectAllCommand(object parameter)
         {
@@ -2777,8 +2768,8 @@ namespace AIStudio.Wpf.DiagramDesigner
             }
             else if (DiagramOption.ShortcutOption.Next(e))
             {
-                NextCommand.Execute(null);
-                return true;
+                //NextCommand.Execute(null);
+                return Next();
             }
             return false;
         }
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BlockViewModel/BlockDesignerItemViewModel.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BlockViewModel/BlockDesignerItemViewModel.cs
index 599e44b..c1e0ed7 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BlockViewModel/BlockDesignerItemViewModel.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BlockViewModel/BlockDesignerItemViewModel.cs
@@ -469,23 +469,35 @@ namespace AIStudio.Wpf.DiagramDesigner
 
         public async Task Execute()
         {
-            await BeforeExecute();
-            await Executing();
-            await AfterExecute();
+            await StopExecution();
+            await BeforeExecution();
+            if (await Executing())
+            {
+                await AfterExecution();
+            }
+            else
+            {
+                IsExecuting = false;
+            }
         }
 
-        public virtual Task BeforeExecute()
+        public virtual Task BeforeExecution()
         {
             IsExecuting = true;
             return Task.CompletedTask;
         }
 
-        public virtual Task Executing()
+        public virtual Task<bool> Executing()
+        {
+            return Task.FromResult(true);
+        }
+
+        public virtual Task StopExecution()
         {
             return Task.CompletedTask;
         }
 
-        public virtual async Task AfterExecute()
+        public virtual async Task AfterExecution()
         {
             if (IsExecuting)
             {
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/Interface/IDiagramViewModel.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/Interface/IDiagramViewModel.cs
index 97c56a4..6c084f7 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/Interface/IDiagramViewModel.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/Interface/IDiagramViewModel.cs
@@ -41,10 +41,6 @@ namespace AIStudio.Wpf.DiagramDesigner
         {
             get;
         }
-        ICommand NextCommand
-        {
-            get;
-        }
         ICommand AlignTopCommand
         {
             get;
@@ -340,6 +336,8 @@ namespace AIStudio.Wpf.DiagramDesigner
 
         void Delete(object parameter);
 
+        bool Next();
+
         void ClearSelectedItems();
 
         bool ExecuteShortcut(KeyEventArgs e);
diff --git a/Extensions/AIStudio.Wpf.Mind/ViewModels/MindDiagramViewModel.cs b/Extensions/AIStudio.Wpf.Mind/ViewModels/MindDiagramViewModel.cs
index 7868300..437bc7c 100644
--- a/Extensions/AIStudio.Wpf.Mind/ViewModels/MindDiagramViewModel.cs
+++ b/Extensions/AIStudio.Wpf.Mind/ViewModels/MindDiagramViewModel.cs
@@ -620,9 +620,17 @@ namespace AIStudio.Wpf.Mind.ViewModels
                  });
         }
 
-        public override void ExecuteNextCommand(object parameter)
+        public override bool Next()
         {
-            ExecuteAddPearCommand(parameter);
+            if (SelectedItems.Count > 0)
+            {
+                ExecuteAddPearCommand(null);
+                return true;
+            }
+            else
+            {
+                return false;
+            }
         }
 
         private void ExecuteMoveBackCommand(object parameter)