Public Class Form1
 
    Private Sub TextBox1_KeyDown(sender As Object, e As KeyEventArgs) Handles _
      TextBox1.KeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            Button1.Focus()
        ElseIf e.KeyCode = 9 Then
            TextBox2.Focus()
        End If
    End Sub
 
    Private Sub TextBox2_KeyDown(sender As Object, e As KeyEventArgs) Handles _
      TextBox2.KeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            TextBox1.Focus()
        ElseIf e.KeyCode = 9 Then
            RadioButton1.Focus()
        End If
    End Sub
 
    Private Sub RadioButton1_KeyDown(sender As Object, e As KeyEventArgs) _
      Handles RadioButton1.KeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            TextBox2.Focus()
        ElseIf e.KeyCode = 9 Then
            RadioButton2.Focus()
        End If
    End Sub
 
    Private Sub RadioButton2_KeyDown(sender As Object, e As KeyEventArgs) _
      Handles RadioButton2.KeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            RadioButton1.Focus()
        ElseIf e.KeyCode = 9 Then
            Button1.Focus()
        End If
    End Sub
 
 
    Private Sub Button1_KeyDown(sender As Object, e As KeyEventArgs) Handles _
      Button1.KeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            RadioButton2.Focus()
        ElseIf e.KeyCode = 9 Then
            TextBox1.Focus()
        End If
    End Sub
 
    Private Sub RadioButton2_PreviewKeyDown(sender As Object, e As _
      PreviewKeyDownEventArgs) Handles RadioButton2.PreviewKeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            RadioButton1.Focus()
        ElseIf e.KeyCode = 9 Then
            Button1.Focus()
        End If
    End Sub
 
    Private Sub RadioButton1_PreviewKeyDown(sender As Object, e As _
      PreviewKeyDownEventArgs) Handles RadioButton1.PreviewKeyDown
        If e.Shift = True And e.KeyCode = 9 Then
            RadioButton2.Focus()
        ElseIf e.KeyCode = 9 Then
            TextBox1.Focus()
        End If
    End Sub
End Class