private void format_controls()
{
set_define_events();
this.MaximizeBox = true;
this.MinimizeBox = true;
this.ShowInTaskbar = true;
this.HelpButton = false;
m_panel_hide.Height = 23;
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
m_tab.SelectedTab = m_tabPage_tong_thu_nhap;
set_active_button(button_enum.tong_thu_nhap);
}