private void MDIParent1_Load(object sender, EventArgs e) { Controller control = new Controller(); this.controller = control; this.controller.ControllerChanged += controller_ControllerChanged; Form1 f1 = new Form1(control); f1.TopLevel = false; f1.Dock = DockStyle.Fill; this.panel1.Controls.Add(f1); f1.Show(); Form2 f2 = new Form2(control); f2.TopLevel = false; f2.Dock = DockStyle.Fill; this.panel2.Controls.Add(f2); f2.Show(); }