<menu> under <toolitem> in ui

[Allin Cottrell <cottrell wfu edu>]

I'm trying to get a button on a toolbar to produce a menu.
The GtkUIManager docs indicate this can be done but I haven't got
the details right yet and I wonder if someone can put me on the
right track.

The ui definition is like this:

const gchar *my_ui =
    "<ui>"
    " <toolbar name='ToolBar'>"
    "   <toolitem action='TopicsButton'>"
    "     <menu action='Topics'>"
    "      <placeholder name='TopicsMenuItems'/>"
    "     </menu>"
    "   </toolitem>"
    "   <toolitem action='WindowFind'/>"
    "   <toolitem action='ZoomIn'/>"
    "   <toolitem action='ZoomOut'/>"
    " </toolbar>"
    "</ui>";

I.e. the first toolitem carries a menu (to be constructed
dynamicallly) but the others are simple buttons.

And I have this array of GtkActionEntry:

GtkActionEntry my_menu_items[] = {
    { "Topics", NULL, NULL, NULL, NULL, NULL },
    { "WindowFind", GTK_STOCK_FIND,
      N_("_Find in window"), NULL, NULL, G_CALLBACK(text_find) },
    { "ZoomIn", GTK_STOCK_ZOOM_IN, N_("_Larger"), NULL, NULL,
      G_CALLBACK(text_zoom) },
    { "ZoomOut", GTK_STOCK_ZOOM_OUT, N_("_Smaller"), NULL, NULL,
      G_CALLBACK(text_zoom) }
};

The action 'TopicsButton' doesn't have an entry in this array
because, as I understand it, I have to create a special GtkAction
with a proxy connected, as in:

    GtkAction *action;
    GtkToolItem *proxy;

    action = gtk_action_new("TopicsButton", NULL, N_("_Topics"),
                            GTK_STOCK_INDEX);
    proxy = gtk_menu_tool_button_new(NULL, NULL);
    gtk_action_connect_proxy(action, GTK_WIDGET(proxy));

I then:

1. use gtk_action_group_add_action_with_accel() to add the
TopicsButton action to a newly created GtkActionGroup.

2. append the actions from the array above using
gtk_action_group_add_actions().

3. use gtk_ui_manager_new() to get a manager, and use
gtk_ui_manager_insert_action_group() to add the whole group.

4. use gtk_ui_manager_add_ui_from_string() with 'my_ui' as
argument.

The toolbar is shown, but the button that's supposed to carry
a menu has no "down arrow" and I get this message:

Gtk-CRITICAL **: gtk_menu_tool_button_set_menu: assertion
`GTK_IS_MENU_TOOL_BUTTON (button)' failed

Allin Cottrell