This one happens when an add-in:

– Creates a temporary toolbar using CommandBars.Add

– Creates a temporary CommandBarPopup on that toolbar

– Creates a command and tries to add a CommandBarButton from that command to that CommandBarPopup using Command.Add(CommandBarPopup.CommandBar)

The bug report is here:

VS 2010 Beta 2 Bug: adding CommandBarButton from Command to CommandbarPopup on Toolbar causes VS to hang

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=503871

The (VB.NET) code to reproduce the problem is:

Imports System
Imports Microsoft.VisualStudio.CommandBars
Imports Extensibility
Imports EnvDTE
Imports EnvDTE80

Public Class Connect
   Implements IDTExtensibility2

   Private _applicationObject As DTE2
   Private _addInInstance As AddIn
   Private _myCommandBarToolbar As CommandBar
   Private _myCommandBarPopup As CommandBarPopup

   Public Sub OnConnection(ByVal application As Object, ByVal connectMode As ext_ConnectMode, ByVal addInInst As Object, ByRef custom As Array) Implements IDTExtensibility2.OnConnection

      _applicationObject = CType(application, DTE2)
      _addInInstance = CType(addInInst, AddIn)

      Select Case connectMode

         Case ext_ConnectMode.ext_cm_AfterStartup
            InitializeAddIn()

         Case ext_ConnectMode.ext_cm_Startup
            ' OnStartupComplete will be called

      End Select

   End Sub

   Public Sub OnStartupComplete(ByRef custom As Array) Implements IDTExtensibility2.OnStartupComplete
      InitializeAddIn()
   End Sub

   Private Sub InitializeAddIn()

      Const MY_COMMAND_NAME As String = "MyCommand"

      Dim command As Command = Nothing
      Dim commandBars As CommandBars
      Dim commandBarControlObject As Object

      Try

         commandBars = CType(_applicationObject.CommandBars(), CommandBars)

         _myCommandBarToolbar = commandBars.Add(Name:="My toolbar", Position:=MsoBarPosition.msoBarTop)

         ' Create a commandbar popup
         _myCommandBarPopup = CType(_myCommandBarToolbar.Controls.Add(Type:=MsoControlType.msoControlPopup), CommandBarPopup)
         _myCommandBarPopup.Caption = "My CommandBarPopup"

         ' Try to retrieve existing command
         Try
            command = _applicationObject.Commands.Item(_addInInstance.ProgID & "." & MY_COMMAND_NAME)
         Catch ex As Exception
         End Try

         ' Create command
         If command Is Nothing Then
            command = _applicationObject.Commands.AddNamedCommand(_addInInstance, MY_COMMAND_NAME, "My command", "My tooltip", True, 59)
         End If

         ' This line hangs VS 2010 Beta 2
         commandBarControlObject = command.AddControl(_myCommandBarPopup.CommandBar)

      Catch ex As Exception
         System.Windows.Forms.MessageBox.Show(ex.ToString)
      End Try

   End Sub

   Public Sub OnDisconnection(ByVal disconnectMode As ext_DisconnectMode, ByRef custom As Array) Implements IDTExtensibility2.OnDisconnection

      Try

         If Not _myCommandBarPopup Is Nothing Then
            _myCommandBarPopup.Delete()
         End If

         If Not _myCommandBarToolbar Is Nothing Then
            _myCommandBarToolbar.Delete()
         End If

      Catch ex As Exception
         System.Windows.Forms.MessageBox.Show(ex.ToString)
      End Try

   End Sub

   Public Sub OnAddInsUpdate(ByRef custom As Array) Implements IDTExtensibility2.OnAddInsUpdate
   End Sub

   Public Sub OnBeginShutdown(ByRef custom As Array) Implements IDTExtensibility2.OnBeginShutdown
   End Sub

End Class