(update_one_menu_entry): When creating a pulldown

in an existing but empty menu item, in order to get a new functional
pulldown, the menu item must be switched from an XmPushButtonGadget
into a XmCascadeButtonGadget.

diff --git a/lwlib/lwlib-Xm.c b/lwlib/lwlib-Xm.c
index c5da97f85ed4e60f8844e75dcd8f39f874951f12..38713adb25f284226bfc0e9912129867338c8333 100644 (file)
--- a/lwlib/lwlib-Xm.c
+++ b/lwlib/lwlib-Xm.c
@@ -509,11 +509,41 @@ update_one_menu_entry (instance, widget, val, deep_p)
     {
       if (contents)
        {
-         menu = XmCreatePulldownMenu (XtParent (widget), XtName (widget), NULL, 0);
+         unsigned int old_num_children, i;
+         Widget button, parent;
+         Widget *widget_list;
+         int buttonchange;
+
+         parent = XtParent (widget);
+         widget_list = XtCompositeChildren (parent, &old_num_children);
+
+         /* Find the widget position within the parent's widget list.  */
+         for (i = 0; i < old_num_children; i++)
+           if (strcmp (XtName (widget_list[i]), XtName (widget)) == 0)
+             break;
+         if (i == old_num_children)
+           abort ();
+         /* `buttonchange' indicates the parent button is being
+            exchanged with a CascadeButton.  */
+         buttonchange = !XmIsCascadeButton (widget_list[i]);
+         if (buttonchange)
+           XtDestroyWidget (widget_list[i]);
+         menu = XmCreatePulldownMenu (parent, val->name, NULL, 0);
          make_menu_in_widget (instance, menu, contents, 0);
          ac = 0;
          XtSetArg (al [ac], XmNsubMenuId, menu); ac++;
-         XtSetValues (widget, al, ac);
+          /* Non-zero values don't work reliably in
+             conjunction with Emacs' event loop */
+          XtSetArg (al [ac], XmNmappingDelay, 0); ac++;
+         /* Tell Motif to put it in the right place.  */
+         XtSetArg (al [ac], XmNpositionIndex, i); ac++;
+         button = XmCreateCascadeButtonGadget (parent, val->name, al, ac);
+         xm_update_label (instance, button, val);
+         
+         XtAddCallback (button, XmNcascadingCallback, xm_pull_down_callback,
+                        (XtPointer)instance);
+         if (buttonchange)
+           XtManageChild (button);
        }
     }
   else if (!contents)
@@ -575,7 +605,10 @@ xm_update_menu (instance, widget, val, deep_p)
       for (i = 0, cur = val->contents; i < num_children_to_keep; i++)
        {
          if (!cur)
-           abort ();
+           {
+             num_children_to_keep = i;
+             break;
+           }
          if (children [i]->core.being_destroyed
              || strcmp (XtName (children [i]), cur->name))
            continue;