private void button1_Click(object sender, EventArgs e) { if (this.MdiChildren.Length != 0) { foreach (Form child in this.MdiChildren) { child.Close(); } } doctorsMenu = new Doctors(this); doctorsMenu.Show(); doctorsMenu.Left = 0; doctorsMenu.Top = 0; doctorsMenu.Size = this.ClientRectangle.Size; doctorsMenu.WindowState = FormWindowState.Maximized; }