A [keybinding signal][class.Gtk.SignalAction] which gets emitted when the user selects all items.
Applications should not connect to it, but may emit it with
g_signal_emit_by_name() if they need to control selection programmatically.
The default binding for this signal is Ctrl-a.
|Default handler:|| |
The default handler is called after the handlers added via
|The signal can be emitted directly|