Although there is documentation with the WOW Extensions Designer that discusses the various properties and events available, there isn't a working example of how to read the properties.

The MonthCal control uses the MONTHCAL-SYSTEMTIMES definition in the Windows.cpy copy file.   For example to obtain the selected date you should use the following code:

Call WowGetProp using win-return monthcal1-h "date"  mc-date1.

See the attached example.