Public Class Form1
 
 Private Sub Form1_MouseDown(sender As Object, _
      e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
     If e.Location.X > Me.Width - 20 Or e.Location.Y > Me.Height - 20 Then
        Cursor = Cursors.SizeAll
     End If
 End Sub
 
 Private Sub Form1_MouseUp(sender As Object, _
     e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseUp
       If Cursor = Cursors.SizeAll Then
         'Mindestgröße sicherstellen
         If e.Location.X > 200 And e.Location.Y > 200 Then
           Me.Width = e.Location.X
           Me.Height = e.Location.Y
         End If
         Cursor = Cursors.Default
      end if 
 End Sub
 
End Class