Execute below code to hide the content pane in AX 2009.
static void hideContentPane(Args _args)
{
#WinApi
HWND contentPane = WinApi::findWindowEx(WinAPI::findWindowEx(infolog.hWnd(), 0, 'MDIClient', ''),0,'ContentFrame','' );
;
if (contentPane)
WinApi::ShowWindow(contentPane, #SW_HIDE);
//Change to #SW_SHOWNORMAL when you want it back
}
/Ashlesh