Counting Lines in RichBox with labels

[Korupt]

Well i im trying to make a panel add a label with a that's text is +1 of the previous (starting from zero) each time enter is pressed in a rich Text Box, using the keyUp event but for some reason it only works in the first time I press enter and after that nothing happens, here the code i got so far:

        private void richTextBox1_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyData == Keys.Enter)
            {
                int number = int.Parse(labelK.Text);
                if (number != 0)
                {
                    number++;
                    int Ypoint = number * 13;
                    int Y = 13 + Ypoint;
                    Label label = new Label();
                    label.Name = "label" + number.ToString();
                    label.Location = new Point(3, Y);
                    label.Text = number.ToString();
                    panel1.Controls.Add(label);
                }
                else
                {
                    number++;
                    Label label = new Label();
                    label.Name = "label" + number.ToString();
                    label.Location = new Point(3, 13);
                    label.Text = number.ToString();
                    panel1.Controls.Add(label);
                }
            }
        }

Any ideas on how to many it work are appreciated.