These docs are for an old release. Info on upgrading to v4
edit doc

eventConstraint

Limits event dragging and resizing to certain windows of time.

an event ID, "businessHours", object

If an event ID is given (most likely a string), events that are being dragged or resized must be fully contained by at least one of the events linked to by the given event ID.

If "businessHours" is given, events being dragged or resized must be fully contained within the week’s business hours (Monday-Friday 9am-5pm by default). A custom businessHours value will be respected.

A custom time-window, an object identical to what businessHours accepts, can also be given:

{
  start: '10:00', // a start time (10am in this example)
  end: '18:00', // an end time (6pm in this example)

  dow: [ 1, 2, 3, 4 ]
  // days of week. an array of zero-based day of week integers (0=Sunday)
  // (Monday-Thursday in this example)
}

A specific period of time with concrete start/end dates can also be given, similar to what an Event Object accepts:

{
  start: '2014-12-01T10:00:00',
  end: '2014-12-05T22:00:00'
}

For more granular control over constraining event dates/times, use the constraint property on an Event Source or the constraint property on an Event Object. View a demo that does this.

If you are using a resource view and would like to constrain an event to cerain resources, read this article.

Resources

The resourceId and resourceIds (an array) properties can be applied to force an event to stay within specific resources:

$('#calendar').fullCalendar({
  defaultView: 'timelineWeek',
  resources: [
    // resource data...
  ]
  events: [
    {
      title: 'my event',
      start: '2016-01-01',
      resourceId: 'b' // start out in resource 'b'
      constraint: {
        resourceIds: [ 'a', 'b', 'c' ] // constrain dragging to these
      }
    }
  ]
});

Only available with the Scheduler plugin.