diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DesignerItemViewModelBase.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DesignerItemViewModelBase.cs
index 0b46d91..a49a791 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DesignerItemViewModelBase.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DesignerItemViewModelBase.cs
@@ -74,7 +74,7 @@ namespace AIStudio.Wpf.DiagramDesigner
                 }
             }
         }
-        #region 属性
+        #region 
 
         public FullyCreatedConnectorInfo FirstConnector
         {
@@ -369,6 +369,17 @@ namespace AIStudio.Wpf.DiagramDesigner
             }
             set
             {
+                if (Root?.DiagramOption?.LayoutOption?.BeyondBoundary > 0)
+                {
+                    if (value + GetItemWidth() < Root.DiagramOption.LayoutOption.BeyondBoundary)
+                    {
+                        value = Root.DiagramOption.LayoutOption.BeyondBoundary - GetItemWidth();
+                    }
+                    else if (value > Root.DiagramOption.LayoutOption.PageSize.Width - Root.DiagramOption.LayoutOption.BeyondBoundary)
+                    {
+                        value = Root.DiagramOption.LayoutOption.PageSize.Width - Root.DiagramOption.LayoutOption.BeyondBoundary;
+                    }
+                }
                 SetProperty(ref _left, value);
             }
         }
@@ -384,6 +395,17 @@ namespace AIStudio.Wpf.DiagramDesigner
             }
             set
             {
+                if (Root?.DiagramOption?.LayoutOption?.BeyondBoundary > 0)
+                {
+                    if (value + GetItemHeight() < Root.DiagramOption.LayoutOption.BeyondBoundary)
+                    {
+                        value = Root.DiagramOption.LayoutOption.BeyondBoundary - GetItemHeight();
+                    }
+                    else if (value > Root.DiagramOption.LayoutOption.PageSize.Height - Root.DiagramOption.LayoutOption.BeyondBoundary)
+                    {
+                        value = Root.DiagramOption.LayoutOption.PageSize.Height - Root.DiagramOption.LayoutOption.BeyondBoundary;
+                    }
+                }
                 SetProperty(ref _top, value);
             }
         }
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramOption.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramOption.cs
index 49ffc2c..9594c7a 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramOption.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/DiagramOption.cs
@@ -112,7 +112,7 @@ namespace AIStudio.Wpf.DiagramDesigner
                 case PageSizeType.ESheet: size = new Size(863.6, 1117.6); break;
             }
 
-            return new Size(ScreenHelper.MmToWidth(size.Width), ScreenHelper.MmToWidth(size.Height));
+            return new Size(size.Width, size.Height);
         }
 
         private PageSizeOrientation _pageSizeOrientation;
@@ -370,6 +370,11 @@ namespace AIStudio.Wpf.DiagramDesigner
         {
             get; set;
         } = true;
+
+        public double BeyondBoundary
+        {
+            get; set;
+        } = -1;
     }
 
     public class SnappingOption
diff --git a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs
index 12e1966..5ff0997 100644
--- a/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs
+++ b/AIStudio.Wpf.DiagramDesigner/ViewModels/BaseViewModel/SelectableViewModelBase.cs
@@ -142,6 +142,11 @@ namespace AIStudio.Wpf.DiagramDesigner
             AnimationViewModel = CopyHelper.Mapper(designerbase.AnimationItem);
         }
 
+        public object Tag
+        {
+            get; set;
+        }
+
         public bool IsLoaded
         {
             get; set;