The following behavior occurs when using WIN32_NATIVECTLS (set to “1” or “ON”) runtime variable on Windows 7:
The DateTimePicker control generates an NTF-CHANGED event when either the month or day is clicked or changed. The expected behavior is to only generate an NTF-CHANGED when dates are clicked or changed.
The additional month NTF-CHANGED event behavior does not occur when using WIN32_NATIVECTLS on Windows XP.
Microsoft significantly modified the Windows 7 DateTimePicker control behavior. Windows XP versions of this control send an NTF-CHANGED event when a date is selected. With Windows 7, the control also sends an NTF-CHANGED event when the month is changed.
On Windows 7 and when using the WIN32_NATIVECTLS runtime variable (set to “1” or “ON”) you will receive an NTF-CHANGED event when the month is changed. You should be aware of this event and handle it with COBOL logic.