How to display a label as message window in Motif MainWindow

I want to use the Motif MainWindow using:

• A container as work region
• A label as message window.

But the label is not shown.

My expectation is that it would be shown below the container (work region).

This is what I have tried:

/* demo_mainwindow_container.c — minimal Motif 2.0 MainWindow + Container + message label
 *
 * Build:
 *   cc demo_mainwindow_container.c -o demo_mainwindow_container -lXm -lXt -lX11
 */

#include <Xm/Xm.h>
#include <Xm/MainW.h>
#include <Xm/Container.h>
#include <Xm/IconG.h>
#include <Xm/Label.h>
#include <stdio.h>

int
main(int argc, char **argv)
{
    XtAppContext app;
    Widget toplevel, main_w, container, status;
    Widget node1, node2, item;
    Arg args[20];
    int n, i;
    XmString s;
    char name[32];
    char label[32];

    XtSetLanguageProc(NULL, NULL, NULL);
    toplevel = XtVaAppInitialize(&app, "XmlviewDemo", NULL, 0, &argc, argv, NULL, NULL);

    /* MAIN WINDOW */
    n = 0;
    XtSetArg(args[n], XmNwidth, 800);                             n++;
    XtSetArg(args[n], XmNheight, 600);                            n++;
    XtSetArg(args[n], XmNscrollBarDisplayPolicy, XmAS_NEEDED);    n++;
    XtSetArg(args[n], XmNscrollingPolicy, XmAUTOMATIC);           n++;
    XtSetArg(args[n], XmNshowSeparator, True);                    n++;
    main_w = XmCreateMainWindow(toplevel, "main_w", args, n);
    XtManageChild(main_w);

    /* WORK AREA: CONTAINER */
    n = 0;
    XtSetArg(args[n], XmNlayoutType, XmOUTLINE);        n++;
    XtSetArg(args[n], XmNentryViewType, XmSMALL_ICON);  n++;
    container = XmCreateContainer(main_w, "container", args, n);
    XtManageChild(container);

    /* MESSAGE AREA: LABEL */
    s = XmStringCreateLocalized("Status: ready (message window label)");
    n = 0;
    XtSetArg(args[n], XmNlabelString, s);        n++;
    status = XmCreateLabel(main_w, "status", args, n);
    XmStringFree(s);
    XtManageChild(status);

    /* NODE 1 */
    n = 0;
    s = XmStringCreateLocalized("Node 1");
    XtSetArg(args[n], XmNlabelString, s); n++;
    node1 = XmCreateIconGadget(container, "node1", args, n);
    XmStringFree(s);
    XtManageChild(node1);

    /* NODE 2 */
    n = 0;
    s = XmStringCreateLocalized("Node 2");
    XtSetArg(args[n], XmNlabelString, s); n++;
    node2 = XmCreateIconGadget(container, "node2", args, n);
    XmStringFree(s);
    XtManageChild(node2);

    /* CHILDREN FOR NODE 1 */
    for (i = 1; i <= 3; ++i) {
        sprintf(name, "n1_item%d", i);
        sprintf(label, "Item %d", i);

        n = 0;
        s = XmStringCreateLocalized(label);
        XtSetArg(args[n], XmNlabelString, s);     n++;
        XtSetArg(args[n], XmNentryParent, node1); n++;
        item = XmCreateIconGadget(container, name, args, n);
        XmStringFree(s);
        XtManageChild(item);
    }

    /* CHILDREN FOR NODE 2 */
    for (i = 1; i <= 3; ++i) {
        sprintf(name, "n2_item%d", i);
        sprintf(label, "Item %d", i);

        n = 0;
        s = XmStringCreateLocalized(label);
        XtSetArg(args[n], XmNlabelString, s);     n++;
        XtSetArg(args[n], XmNentryParent, node2); n++;
        item = XmCreateIconGadget(container, name, args, n);
        XmStringFree(s);
        XtManageChild(item);
    }

    /* CONNECT WIDGETS INTO MAINWINDOW */
    XtVaSetValues(main_w,
                  XmNworkWindow, container,
                  XmNmessageWindow, status,
                  NULL);

    XtRealizeWidget(toplevel);
    XtAppMainLoop(app);
    return 0;
}

To compile (under FreeBSD):

cc -o test_mainwindow test_mainwindow.c -I/usr/local/include -L/usr/local/lib -lXm -lX11 -lXt

This is the result, and as it can be seen the message window is not displayed:

On the contrary, this example, which uses a text widget displays the label as message label:

#include <Xm/Xm.h>
#include <Xm/MainW.h>
#include <Xm/Label.h>
#include <Xm/Text.h>

int main(int argc, char *argv[])
{
    XtAppContext app;
    Widget toplevel, main_w, label, text;
    XmString label_str;

    /* Initialize top-level shell */
    toplevel = XtVaAppInitialize(&app, "MainWindowExample", NULL, 0,
                                 &argc, argv, NULL, NULL);

    /* Create a MainWindow */
    main_w = XtVaCreateManagedWidget("main_w",
                                     xmMainWindowWidgetClass, toplevel,
                                     NULL);

    /* Create a Text widget for the work area */
    text = XtVaCreateManagedWidget("text",
                                   xmTextWidgetClass, main_w,
                                   XmNrows, 5,
                                   XmNcolumns, 40,
                                   XmNeditMode, XmMULTI_LINE_EDIT,
                                   NULL);

    /* Create a Label for the message area */
    label_str = XmStringCreateLocalized("Ready.");
    label = XtVaCreateManagedWidget("label",
                                    xmLabelWidgetClass, main_w,
                                    XmNlabelString, label_str,
                                    NULL);
    XmStringFree(label_str);

    /* Assign text as work area and label as message area */
    XmMainWindowSetAreas(main_w,
                         NULL,     /* menu bar */
                         NULL,     /* command window */
                         NULL,     /* horizontal scrollbar */
                         NULL,     /* vertical scrollbar */
                         text);    /* work area */
    XtVaSetValues(main_w, XmNmessageWindow, label, NULL);

    /* Realize and enter event loop */
    XtRealizeWidget(toplevel);
    XtAppMainLoop(app);

    return 0;
}

I can not find why one works and the other does not.