diff --git a/.github/workflows/nuget.yml b/.github/workflows/nuget.yml
index 5bdeba6..1598638 100644
--- a/.github/workflows/nuget.yml
+++ b/.github/workflows/nuget.yml
@@ -29,4 +29,43 @@ jobs:
       
     - name: Publish NuGet
       run: dotnet nuget push src\bin\${{ matrix.version }}\*.nupkg -k ${{secrets.NUGETKEY}} -s https://api.nuget.org/v3/index.json --skip-duplicate
+      
+    - name: Delete old packages
+      shell: pwsh
+      run: |
+        # 获取包名称
+        $packageId = "Tuna.Revit.Extension"
+        # 保留最新的N个版本
+        $versionsToKeep = 10
+        
+        # 获取包的详细信息
+        $baseUrl = "https://api.nuget.org/v3/registration5-semver1/$packageId/index.json"
+        $response = Invoke-RestMethod -Uri $baseUrl
+        
+        # 获取所有版本及其发布时间
+        $versionDetails = @()
+        foreach ($item in $response.items) {
+            foreach ($entry in $item.items) {
+                $versionDetails += @{
+                    Version = $entry.catalogEntry.version
+                    Published = [DateTime]::Parse($entry.catalogEntry.published)
+                }
+            }
+        }
+        
+        # 按发布时间排序并选择要删除的版本
+        $versionsToDelete = $versionDetails | 
+            Sort-Object Published -Descending | 
+            Select-Object -Skip $versionsToKeep | 
+            Select-Object -ExpandProperty Version
+        
+        foreach ($version in $versionsToDelete) {
+            Write-Host "Deleting version $version of $packageId (Published: $($versionDetails | Where-Object Version -eq $version | Select-Object -ExpandProperty Published))"
+            # 删除包版本
+            Invoke-RestMethod -Uri "https://api.nuget.org/v3/packages/$packageId/$version" `
+                -Method Delete `
+                -Headers @{
+                    'X-NuGet-ApiKey' = '${{secrets.NUGETKEY}}'
+                }
+        }
 
diff --git a/src/Geometry/TransientElementExtensions.cs b/src/Geometry/TransientElementExtensions.cs
index 4fc5981..16b66c0 100644
--- a/src/Geometry/TransientElementExtensions.cs
+++ b/src/Geometry/TransientElementExtensions.cs
@@ -93,13 +93,14 @@ public static void CleanTransientElements(this Document document)
 
         document.NewTransaction(() =>
         {
-            foreach (var elementId in _transientElementIds)
+            for (int i = _transientElementIds.Count - 1; i >= 0; i--)
             {
-                Element element = document.GetElement(elementId);
+                ElementId currentId = _transientElementIds[i];
+                Element element = document.GetElement(currentId);
                 if (element != null)
                 {
-                    document.Delete(elementId);
-                    _transientElementIds.Remove(elementId);
+                    document.Delete(currentId);
+                    _transientElementIds.Remove(currentId);
                 }
             }
         });
diff --git a/src/Selection/SelectionChangedEventArgs.cs b/src/Selection/SelectionChangedEventArgs.cs
index 24cfc6a..e23e117 100644
--- a/src/Selection/SelectionChangedEventArgs.cs
+++ b/src/Selection/SelectionChangedEventArgs.cs
@@ -24,15 +24,15 @@ internal SelectionChangedEventArgs(Autodesk.Revit.UI.Events.SelectionChangedEven
     /// <summary>
     /// 发生选择变更的文档
     /// </summary>
-    public Document Document { get; }
+    public Document? Document { get; }
 
     /// <summary>
     /// 被选择的图元 <see cref="Autodesk.Revit.DB.ElementId"/>
     /// </summary>
-    public IEnumerable<ElementId> Elements { get; }
+    public IEnumerable<ElementId>? Elements { get; }
 
     /// <summary>
     /// 被选择的引用 <see cref="Autodesk.Revit.DB.Reference"/>
     /// </summary>
-    public IEnumerable<Reference> References { get; }
+    public IEnumerable<Reference>? References { get; }
 }
diff --git a/src/Tuna.Revit.Extension.csproj b/src/Tuna.Revit.Extension.csproj
index ad1300c..5d21aa3 100644
--- a/src/Tuna.Revit.Extension.csproj
+++ b/src/Tuna.Revit.Extension.csproj
@@ -29,7 +29,7 @@
 			Rvt_24_Debug;Rvt_24_Release;
 			Rvt_25_Debug;Rvt_25_Release;
 		</Configurations>
-		<TunaVer>19</TunaVer>
+		<TunaVer>19.1</TunaVer>
 		<PlatformTarget>x64</PlatformTarget>
 		<LangVersion>preview</LangVersion>
 		<Nullable>enable</Nullable>