private void form_element_Shown(object sender, EventArgs e)
        {
            double[] harga_element = ((form_main)this.Owner).get_harga_element();
            TextBox  t;

            for (int i = 0; i < 5; i++)
            {
                t      = (TextBox)this.Controls.Find("txt_butuh_" + i, true)[0];
                t.Text = harga_element[i].ToString();
            }
            form_main f = (form_main)this.Owner;

            this.Location = new Point(f.Location.X + f.Size.Width, f.Location.Y);
        }
        private void form_element_LocationChanged(object sender, EventArgs e)
        {
            form_main f = (form_main)this.Owner;

            f.Location = new Point(this.Location.X - this.Size.Width, this.Location.Y);
        }