By default, the CondnsideZoom property is empty. If empty, the CondInsideZoom property has no effect. If the  CondInsideZoom property is not empty and valid, it indicates the dates that can be magnified by double clicking the time unit in the base level, if the InsideZoomOnDblClick property is True, or by resizing the time unit, if the AllowResizeInsideZoom property is True. In other words, the CondInsideZoom property has effect ONLY if the AllowResizeInsideZoom or InsideZoomOnDblClick properties. So, it has no effect when adding the inside zoom units by code, using the Add method. 

The expression may be a combination of variables, constants, strings, dates and operators, and value. The value operator gives the date-time expression being checked.  A string is delimited by ", ` or ' characters, and inside they can have the starting character preceded by \ character, ie "\"This is a quote\"". A date is delimited by # character, ie #1/31/2001 10:00# means the January 31th, 2001, 10:00 AM.

For instance, if the CondInsideZoom property is "weekday(value) = 0" means that you allow zooming only for Sundays, or if it is "not(weekday(value) = 0 or weekday(value) = 6)" the control allow zooming only for working dates, as Monday to Friday. 

The value keyword in the CondInsideZoom property indicates the date-time expression being checked. 

This property/method supports predefined constants and operators/functions as described here.