Visual Basic

Dim newChildForm As New Form2
... other MDI setup stuff
newChildForm.Top = 100
newChildForm.Left = 100
newChildForm.Show()

Dim originalPosition As String

Private sub [tried several methods]

originalPosition = TreeView1.SelectedNode.FullPath [...tried multiple properties]

End sub

Public Sub TreeView1_ItemDrag(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ItemDragEventArgs) Handles TreeView1.ItemDrag
    DoDragDrop(e.Item, DragDropEffects.Move)
End Sub

Public Sub TreeView1_DragEnter(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragEnter

    If e.Data.GetDataPresent("System.Windows.Forms.TreeNode", True) Then
        e.Effect = DragDropEffects.Move
    Else
        e.Effect = DragDropEffects.None
    End If
End Sub

Private Sub TreeView1_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragOver
    If e.Data.GetDataPresent("System.Windows.Forms.TreeNode", True) = False Then Exit Sub

    Dim selectedTreeview As TreeView = CType(sender, TreeView)
    Dim pt As Point = CType(sender, TreeView).PointToClient(New Point(e.X, e.Y))
    Dim targetNode As TreeNode = selectedTreeview.GetNodeAt(pt)

    If Not (selectedTreeview Is targetNode) Then
        selectedTreeview.SelectedNode = targetNode
        Dim dropNode As TreeNode = CType(e.Data.GetData("System.Windows.Forms.TreeNode"), TreeNode)
        Do Until targetNode Is Nothing
            If targetNode Is dropNode Then
                e.Effect = DragDropEffects.None
                Exit Sub
            End If
            targetNode = targetNode.Parent
        Loop
    End If

    e.Effect = DragDropEffects.Move
End Sub

Private Sub TreeView1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles TreeView1.DragDrop
    If e.Data.GetDataPresent("System.Windows.Forms.TreeNode", _
          True) = False Then Exit Sub

    Dim selectedTreeview As TreeView = CType(sender, TreeView)
    Dim dropNode As TreeNode = _
          CType(e.Data.GetData("System.Windows.Forms.TreeNode"), _
          TreeNode)

    Dim targetNode As TreeNode = selectedTreeview.SelectedNode

    dropNode.Remove()
    If targetNode Is Nothing Then
        selectedTreeview.Nodes.Add(dropNode)
    Else
        targetNode.Nodes.Add(dropNode)
    End If
    dropNode.EnsureVisible()
    selectedTreeview.SelectedNode = dropNode
End Sub