Subscribes a listener to this queue.
It is the same as
subscribe(listener, false)
(
#subscribe(EventListener,boolean). In other words,
it subscribes a synchronous listener.
Note: this method must be called within an activated execution
(i.e.,
org.zkoss.zk.ui.Executions#getCurrent not null),
no matter what scope the event queue is.
Note: the listener could access the component associated with the event
(
Event#getTarget), only if this is an
EventQueues#DESKTOPevent queue.
An event listener can be subscribed multiple times, and
it will be invoked multiple times if an event is published.
Even if this is a
EventQueues#GROUP,
EventQueues#SESSION,
or
EventQueues#APPLICATION event queue,
the listener is subscribed for the current desktop only, i.e.,
it can only access the components belong to the subscribed desktop.
If you want to use the same listener to manipulate multiple desktops,
you have to subscribe them separately when the corresponding
execution is available.