How to change the MDI layout when using raddock

I have a mdi parent with raddock control, I add new forms and I can use the mouse to change the layout of the mdi child in the parent but I cannot make the layoutMDI to work to change the layout

 

this.LayoutMdi(MdiLayout.TileHorizontal);

Just doing something simple to get the idea

 

     private void Form1_Load(object sender, EventArgs e)
        {
            this.IsMdiContainer = true;
            this.radDock1.AutoDetectMdiChildren = true;

            Form form = new Form2();
            form.Text = "MDI Child 1";
            form.MdiParent = this;
          //  form.Show();

            form = new Form2();
            form.Text = "MDI Child 2";
            form.MdiParent = this;
          //  form.Show();

            form = new Form2();
            form.Text = "MDI Child 3";
            form.MdiParent = this;
          //  form.Show();

            this.Show();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            this.LayoutMdi(System.Windows.Forms.MdiLayout.TileHorizontal);
        }