How to create a RichTextBox object - C#

Hi everybody,
How to create a RichTextBox object? Here is code:

RichTextBox objekt;

private void button3_Click(object sender, EventArgs e)

{

objekt = new RichTextBox();
objekt.Location = new Point(5,5); 
objekt.Size = panel12.Size;
 objekt.Visible = true;

}

But I don't see a RichTextbox in my program. What is done bad?

Thanks in advance.