Increasing the height of Panel according to wrapped string Label in Panel

Question

i am trying to develop a win form for chatting purpose. I am developing Chat bubbles using pure inbuilt functions of .Net Framework, No fancy UI, No third party libraries. Now let's have a look on how every thing is being done.

My following function is responsible for generating a Panel dynamically for each chat message received, the Pain event is used to draw rounded rectangle and color is transparent. A picture box is used to show static avatar.

private void SetRemoteMessage(string msg)
        {
            PictureBox pb = new PictureBox();
            pb.Bounds = new Rectangle(0, 0, 72, 72);
            pb.Image = Base64ToImage(avatar_his);

            Panel p = new Panel();
            Label lb = new Label();
            lb.BackColor = Color.Transparent;
            lb.ForeColor = Color.Blue;
            lb.Text = msg;
            lb.Font = new Font("Arial", 14, FontStyle.Bold, GraphicsUnit.Point);

            p.Bounds = new Rectangle(rX, rY, (Width / 2) - 25, pb.Height);
            p.BackColor = Color.Transparent;

            lb.Size = new Size(p.Width - pb.Width, p.Height);
            lb.Paint += _control_Paint;

            lb.Location = new Point(pb.Width + 5, 0);

            p.Controls.Add(pb);
            p.Controls.Add(lb);

            SetPanel(p);

            rY += p.Height + 20;
            mY += p.Height + 20;
        } 

following is the Paint event binded to the parent "Container" Panel so that a simple rounded rectangle is shown for each bubble

private void _control_Paint(object sender, PaintEventArgs e)
        {
            Control c = (Control)sender;

            if(!c.Name.Equals("lb"))
            {
                Graphics v = e.Graphics;
                DrawRoundRect(v, Pens.Blue, e.ClipRectangle.Left, e.ClipRectangle.Top, e.ClipRectangle.Width - 1, e.ClipRectangle.Height - 1, 10);  
            }
            else
            {
                using (Font font1 = new Font("Arial", 12, FontStyle.Bold, GraphicsUnit.Point))
                {
                    e.Graphics.DrawString(c.Text, font1, Brushes.Blue, c.Bounds);
                }
            }

            base.OnPaint(e);
        }

and the following function to actually generate rounded rectangles

private void DrawRoundRect(Graphics g, Pen p, float X, float Y, float width, float height, float radius)
        {
            GraphicsPath gp = new GraphicsPath();
            gp.AddLine(X + radius, Y, X + width - (radius * 2), Y);
            gp.AddArc(X + width - (radius * 2), Y, radius * 2, radius * 2, 270, 90);
            gp.AddLine(X + width, Y + radius, X + width, Y + height - (radius * 2));
            gp.AddArc(X + width - (radius * 2), Y + height - (radius * 2), radius * 2, radius * 2, 0, 90);
            gp.AddLine(X + width - (radius * 2), Y + height, X + radius, Y + height);
            gp.AddArc(X, Y + height - (radius * 2), radius * 2, radius * 2, 90, 90);
            gp.AddLine(X, Y + height - (radius * 2), X, Y + radius);
            gp.AddArc(X, Y, radius * 2, radius * 2, 180, 90);
            gp.CloseFigure();
            g.DrawPath(p, gp);
        }

The chat message is not wrapped automatically so to wrap it, the Pain method is used as it can be seen in Paint event . .the output is good as expected instead of one thing

The Problem can be seen easily the Panel height is not increasing according when a large message is given to display in bubble.

What i tried already is

1. Measuring string length with Graphics class, but i was not able to implement it with success
2. Enabling Scrollbars, Yes this approach worked but i am not interested to use this behavior
3. Counting string length and increasing height, This works but not efficient, specially when form is resized all calculations of measurement then become invalid.