method MarkZones.Add (Key as String, Start as Variant, End as Variant)
Adds a MarkZone object to the collection and returns a reference to the newly created object.

TypeDescription
Key as String A String expression that indicates the key of the time-zone to be added. The Key property of the MarkZone object indicates the key of the newly added time-zone. 
Start as Variant A DATE expression that specifies the starting point of the time-zone. The Start property indicates the  starting point of the time-zone.
End as Variant A DATE expression that specifies the ending point of the time-zone. The End property indicates the ending point of the time-zone.
ReturnDescription
MarkZoneA MarkZone object being added.

Use the Add method of the MarkZones collection to add a new time-zone to the control. The Start property indicates the starting date/time of the time-zone. The End property indicates the starting date/time of the time-zone.  The MarkZones property gets the MarkZones collection. The MarkZones collection holds a set of MarkZone objects ( also called time-zone ). A MarkZone object holds information about a time-zone. A time-zone is identified by a Start/End date time, what can be highlighted in the schedule view. The MarkZoneFromPoint property indicates the time-zone from the cursor. The Start should be less than End property, else the time-zone is not visible. 

The MarkZone object can:

A time-zone ( MarkZone object ) requires the Start/End to define the zone, while a timer ( MarkTime object ) requires a Time, that indicates where the timer is shown.