Dim ExpandOrCollapseAction As Boolean = False
 
    Private Sub TreeView1_AfterCollapse(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterCollapse
        ExpandOrCollapseAction = True
    End Sub
 
    Private Sub TreeView1_AfterExpand(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterExpand
        ExpandOrCollapseAction = True
    End Sub
 
    Private Sub TreeView1_MouseUp(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseUp
        Dim tn As TreeNode = Me.TreeView1.GetNodeAt(e.X, e.Y)
        Dim msg As String = Nothing
        If Not tn Is Nothing AndAlso Not (ExpandOrCollapseAction) Then
            msg = "Es wurde auf ein Node (" + tn.Name + ") geklickt!"
        Else
            msg = "Es wurde auf ein + oder - geklickt!"
        End If
        Debug.WriteLine(msg)
        ExpandOrCollapseAction = False
    End Sub