Sets the #GtkMenuItem used in the toolbar overflow menu. The menu_item_id is used to identify the caller of this function and should also be used with gtk.tool_item.ToolItem.getProxyMenuItem.
See also #GtkToolItem::create-menu-proxy.
a string used to identify menu_item
a #GtkMenuItem to use in the overflow menu, or null
Sets the #GtkMenuItem used in the toolbar overflow menu. The menu_item_id is used to identify the caller of this function and should also be used with gtk.tool_item.ToolItem.getProxyMenuItem.
See also #GtkToolItem::create-menu-proxy.