История изменений

/* Terminology:
 * 
 * A menu item can be "selected", this means that it is displayed
 * in the prelight state, and if it has a submenu, that submenu
 * will be popped up. 
 * 
 * A menu is "active" when it is visible onscreen and the user
 * is selecting from it. A menubar is not active until the user
 * clicks on one of its menuitems. When a menu is active,
 * passing the mouse over a submenu will pop it up.
 *
 * menu_shell->active_menu_item, is however, not an "active"
 * menu item (there is no such thing) but rather, the selected
 * menu item in that MenuShell, if there is one.
 *
 * There is also is a concept of the current menu and a current
 * menu item. The current menu item is the selected menu item
 * that is furthest down in the hierarchy. (Every active menu_shell
 * does not necessarily contain a selected menu item, but if
 * it does, then menu_shell->parent_menu_shell must also contain
 * a selected menu item. The current menu is the menu that 
 * contains the current menu_item. It will always have a GTK
 * grab and receive all key presses.
 *
 *
 * Action signals:
 *
 *  ::move_current (GtkMenuDirection *dir)
 *     Moves the current menu item in direction 'dir':
 *
 *       GTK_MENU_DIR_PARENT: To the parent menu shell
 *       GTK_MENU_DIR_CHILD: To the child menu shell (if this item has
 *          a submenu.
 *       GTK_MENU_DIR_NEXT/PREV: To the next or previous item
 *          in this menu.
 * 
 *     As a a bit of a hack to get movement between menus and
 *     menubars working, if submenu_placement is different for
 *     the menu and its MenuShell then the following apply:
 * 
 *       - For 'parent' the current menu is not just moved to
 *         the parent, but moved to the previous entry in the parent
 *       - For 'child', if there is no child, then current is
 *         moved to the next item in the parent.
 *
 *    Note that the above explanation of ::move_current was written
 *    before menus and menubars had support for RTL flipping and
 *    different packing directions, and therefore only applies for
 *    when text direction and packing direction are both left-to-right.
 * 
 *  ::activate_current (GBoolean *force_hide)
 *     Activate the current item. If 'force_hide' is true, hide
 *     the current menu item always. Otherwise, only hide
 *     it if menu_item->klass->hide_on_activate is true.
 *
 *  ::cancel ()
 *     Cancels the current selection
 */

/* Terminology:
 * 
 * A menu item can be "selected", this means that it is displayed
 * in the prelight state, and if it has a submenu, that submenu
 * will be popped up. 
 * 
 * A menu is "active" when it is visible onscreen and the user
 * is selecting from it. A menubar is not active until the user
 * clicks on one of its menuitems. When a menu is active,
 * passing the mouse over a submenu will pop it up.
 *
 * menu_shell->active_menu_item, is however, not an "active"
 * menu item (there is no such thing) but rather, the selected
 * menu item in that MenuShell, if there is one.
 *
 * There is also is a concept of the current menu and a current
 * menu item. The current menu item is the selected menu item
 * that is furthest down in the hierarchy. (Every active menu_shell
 * does not necessarily contain a selected menu item, but if
 * it does, then menu_shell->parent_menu_shell must also contain
 * a selected menu item. The current menu is the menu that 
 * contains the current menu_item. It will always have a GTK
 * grab and receive all key presses.
 *
 *
 * Action signals:
 *
 *  ::move_current (GtkMenuDirection *dir)
 *     Moves the current menu item in direction 'dir':
 *
 *       GTK_MENU_DIR_PARENT: To the parent menu shell
 *       GTK_MENU_DIR_CHILD: To the child menu shell (if this item has
 *          a submenu.
 *       GTK_MENU_DIR_NEXT/PREV: To the next or previous item
 *          in this menu.
 * 
 *     As a a bit of a hack to get movement between menus and
 *     menubars working, if submenu_placement is different for
 *     the menu and its MenuShell then the following apply:
 * 
 *       - For 'parent' the current menu is not just moved to
 *         the parent, but moved to the previous entry in the parent
 *       - For 'child', if there is no child, then current is
 *         moved to the next item in the parent.
 *
 *    Note that the above explanation of ::move_current was written
 *    before menus and menubars had support for RTL flipping and
 *    different packing directions, and therefore only applies for
 *    when text direction and packing direction are both left-to-right.
 * 
 *  ::activate_current (GBoolean *force_hide)
 *     Activate the current item. If 'force_hide' is true, hide
 *     the current menu item always. Otherwise, only hide
 *     it if menu_item->klass->hide_on_activate is true.
 *
 *  ::cancel ()
 *     Cancels the current selection
 */