Parent to Dll form problems

Question

Hi there.

I have a problem with the parenting in C#. It seems as though I'm missing something. (Searching the web doesn't help).

I want to open multiple forms in a panel on my main form by clicking on a button, but I seem to be doing something wrong. This is the code I'm using:
        public IntPtr Handel1;
        public Control pannelControl;

private void button1_Click(object sender, EventArgs e)
        {
            pannelControl = panel1;
            Handel1 = pannelControl.Handle;
            FORM2 form2 = new FORM2();
            form2.TopMost = false;
            panel1.Controls.Add(form2);
            form2.Show();

        }

public partial class FORM2 : Form
    {
        public void FORM2_Load(object sender, EventArgs e)
        {
           
        }

    }

First of all, The form is empty. This is the exception I'm getting at the line "panel1.Controls.Add(form2);"

ArgumentException was unhandled
Value does not fall within the expected range.