[VBA]怪！这段程序为什么要运行两次才能实现？

Sub Ch6_AddMenuItemToshortcutMenu()
On Error Resume Next
Dim currMenuGroup As AcadMenuGroup
Set currMenuGroup = ThisDrawing.Application.MenuGroups.Item(0)
'找到快捷菜单并赋值它为shortcutMenu变量
Dim scMenu As AcadPopupMenu
Dim entry As AcadPopupMenu
For Each entry In currMenuGroup.Menus
If entry.ShortcutMenu = True Then
Set scMenu = entry
End If
Next entry
' 在快捷菜单中增加菜单项
Dim newMenuItem As AcadPopupMenuItem
Dim openMacro As String
' 为宏赋值VBA表达式"ESC ESC _open "
openMacro = Chr(3) + Chr(3) + Chr(95) + "open" + Chr(32)
Set newMenuItem = scMenu.AddMenuItem("", Chr(Asc("&")) + "OpenDWG", openMacro)
End Sub