Moved Up TreeNode becomes unselectable?

When I move a TreeNode up it becomes unselectable. Why so?

Public Function F_Node_Move_Up() As Boolean
Dim OTreeView As TreeView = Me.TreeView
Dim selectedNode As TreeNode = Me
Dim parentNode As TreeNode = selectedNode.Parent

‘ IF tehere is no parent
Dim nodesCollection As TreeNodeCollection
If parentNode Is Nothing Then
nodesCollection = OTreeView.Nodes
Else
nodesCollection = parentNode.Nodes
End If

‘ Find the node index
Dim currentIndex As Integer = nodesCollection.IndexOf(selectedNode)
If currentIndex <= 0 Then
Return False
End If

‘ Moving of the node
nodesCollection.RemoveAt(currentIndex)
nodesCollection.Insert(currentIndex – 1, selectedNode)

‘Select moved node
nodesCollection(currentIndex – 1).EnsureVisible()
Me.TreeView.SelectedNode = nodesCollection(currentIndex – 1)

Return True
End Function