temporarily blocks triggering of ALL events of the calling object
$$('list').blockEvent();
$$('list').add({ text:'abc'}); //will not trigger list events
$$('list').unblockEvent();
Use the command with care, many actions in components are linked through events.
The most common use-case - preventing a component from repainting with each small operation:
//will repaint component 3 times
$$('list').add({ text:'111'});
$$('list').add({ text:'222'});
$$('list').add({ text:'333'});
//will repaint component only once (onStoreUpdated of List DataStore is blocked)
$$('list').data.blockEvent();
$$('list').add({ text:'111'});
$$('list').add({ text:'222'});
$$('list').add({ text:'333'});
$$('list').data.unblockEvent();
$$('list').refresh();