xfwm4 4.14:

An initial mapped window's title fails to include the " (on WM_CLIENT_MACHINE)" suffix. The suffix gets added when the window's title gets subsequently changed.

The following short program creates a window. The initial title does not have the suffix, and only shows as "Lorem". After a five second delay the window's title gets changed to "Ipsum (on external.example.com)".

#include <unistd.h>
#include <xcb/xcb.h>
#include <xcb/xcb_ewmh.h>
#include <xcb/xcb_icccm.h>

int
main ()
{
        xcb_connection_t *connection = xcb_connect (NULL, NULL);
	xcb_ewmh_connection_t ewmh;
	xcb_generic_error_t *err;

        const xcb_setup_t      *setup  = xcb_get_setup (connection);
        xcb_screen_iterator_t   iter   = xcb_setup_roots_iterator (setup);
        xcb_screen_t           *screen = iter.data;

	xcb_intern_atom_cookie_t *cookie=
		xcb_ewmh_init_atoms(connection, &ewmh);

	xcb_ewmh_init_atoms_replies(&ewmh,
				    cookie,
				    &err);

        xcb_window_t window = xcb_generate_id (connection);

        xcb_create_window (connection,
                           XCB_COPY_FROM_PARENT,
                           window,
                           screen->root,
                           0, 0,
                           400, 400,
                           10,
                           XCB_WINDOW_CLASS_INPUT_OUTPUT,
                           screen->root_visual,
                           0, NULL );

	xcb_icccm_set_wm_client_machine(connection,
					window,
					XCB_ATOM_STRING,
					8,
					20,
					"external.example.com");

	xcb_ewmh_set_wm_name(&ewmh,
			     window,
			     5,
			     "Lorem");

        xcb_map_window (connection, window);

        xcb_flush (connection);

	sleep(5);

	xcb_ewmh_set_wm_name(&ewmh,
			     window,
			     5,
			     "Ipsum");

        xcb_flush (connection);

	sleep(5);

        xcb_disconnect (connection);

        return 0;
}