Events extending {@link com.top_logic.event.bus.BusEvent}.

• DocumentEvent
  This event is used to notify {@link com.top_logic.base.monitor.bus.DocumentMonitor} about changing (Document-)knowledgeobject.
• MonitorEvent
  Base class of all events used with a monitor.
• UserEvent
  This event is used to notify {@link com.top_logic.base.monitor.bus.UserMonitor} about login/logout user.