lambda (item)    :run-last      

The signal is emitted when the toolbar needs information from item about whether the item should appear in the toolbar overflow menu. In response the tool item should either.

• Call the gtk:tool-item-proxy-menu-item function with nil and return true to indicate that the tool item should not appear in the overflow menu,
• call the gtk:tool-item-proxy-menu-item function with a new menu item and return true, or
• return false to indicate that the signal was not handled by the tool item. This means that the tool item will not appear in the overflow menu unless a later handler installs a menu item.

The toolbar may cache the result of this signal. When the tool item changes how it will respond to this signal it must call the gtk:tool-item-rebuild-menu function to invalidate the cache and ensure that the toolbar rebuilds its overflow menu.

lambda (item)    :run-last      

The signal is emitted when some property of the toolbar that the item is a child of changes. For custom subclasses of the gtk:tool-item class, the default handler of this signal use the gtk:tool-shell-orientation, gtk:tool-shell-style, gtk:tool-shell-icon-size, or gtk:tool-shell-relief-style functions to find out what the toolbar should look like and change themselves accordingly.