Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For Each c As Control In GetChildControls(Me)
            If c.Tag = "SI bordo" Then
                AddHandler c.GotFocus, AddressOf ctrl_GotFocus
                AddHandler c.LostFocus, AddressOf ctrl_LostFocus
            End If
        Next
    End Sub

    Private Function GetChildControls(ByVal ctrl As Control) As Control()
        Dim controls As New ArrayList
        For Each c As Control In ctrl.Controls
            controls.Add(c)
            controls.AddRange(GetChildControls(c))
        Next
        Return DirectCast(controls.ToArray(GetType(Control)), Control())
    End Function

    Private Sub ctrl_GotFocus(ByVal sender As System.Object, ByVal e As System.EventArgs)
        Dim g As Graphics = sender.Parent.CreateGraphics
        Dim Penna As New Pen(Color.Red, 2.0)
        g.DrawRectangle(Penna, New Rectangle(sender.Location, sender.Size))
        Penna.Dispose()
        g.Dispose()
    End Sub

    Private Sub ctrl_LostFocus(ByVal sender As System.Object, ByVal e As System.EventArgs)
        Dim g As Graphics = sender.Parent.CreateGraphics
        Dim Penna As New Pen(SystemColors.Control, 2.0)
        g.DrawRectangle(Penna, New Rectangle(sender.Location, sender.Size))
        Penna.Dispose()
        g.Dispose()
    End Sub