Drawing a border gives problems with resizing the form.

Dear Expers,

I have this OnPaint-methode to draw a border around
my borderless form:

        private void StickyNotes_Paint(object sender, PaintEventArgs e)
         {
            using (Pen pen = new Pen(Brushes.Silver, 2))
            {
                e.Graphics.DrawRectangle(pen, this.ClientRectangle);
            }
         }

And it works awsome.
In picture2 you see what happens when I resize my form!

What can I do about this? Who knows the answer and
is willing to help me?

Greetings,

Peter Kiers
Picture1.jpg
Picture2.jpg