private void Form1_Click4(object sender, EventArgs e) { foreach (Form form in Application.OpenForms) { if (form.GetType() == typeof(Form7)) { form.Activate(); return; } // button2.Visible = false; } //button2.Visible = true; Form newForm = new Form7(); newForm.BackColor = Color.Wheat; newForm.MdiParent = this; newForm.Show(); }