private void user_list_btn_Click(object sender, EventArgs e)
        {
            slide_panel.Height = user_list_btn.Height;
            slide_panel.Top    = user_list_btn.Top;
            User_list users_list = new User_list();

            users_list.Show();
        }
        private void user_list_btn_Click(object sender, EventArgs e)
        {
            slide_panel.Width = user_list_btn.Width;
            slide_panel.Left  = user_list_btn.Left;
            User_list users_list = new User_list();

            users_list.Show();
            this.Hide();
        }