Class Ext.form.ComboBox

• scope {Object} The scope in which to execute the handler function. The handler function's "this" context.
• delegate {String} A simple selector to filter the target or look for a descendant of the target
• stopEvent {Boolean} True to stop the event. That is stop propagation, and prevent the default action.
• preventDefault {Boolean} True to prevent the default action
• stopPropagation {Boolean} True to prevent event propagation
• normalized {Boolean} False to pass a browser event to the handler function instead of an Ext.EventObject
• delay {Number} The number of milliseconds to delay the invocation of the handler after te event fires.
• single {Boolean} True to add a handler to handle just the next firing of the event, and then remove itself.
• buffer {Number} Causes the handler to be scheduled to run in an Ext.util.DelayedTask delayed by the specified number of milliseconds. If the event fires again within that time, the original handler is not invoked, but the new handler is scheduled in its place.

Combining Options
Using the options argument, it is possible to combine different types of listeners:

A normalized, delayed, one-time listener that auto stops the event and passes a custom argument (forumId)

el.on('click', this.onClick, this, { single: true, delay: 100, stopEvent : true, forumId: 4 });

el.on({ 'click' : { fn: this.onClick scope: this, delay: 100 }, 'mouseover' : { fn: this.onMouseOver scope: this }, 'mouseout' : { fn: this.onMouseOut scope: this } });

el.on({ 'click' : this.onClick, 'mouseover' : this.onMouseOver, 'mouseout' : this.onMouseOut scope: this });