To be eligible for automatic windowing, a date field should contain a two-digit year as the first or only part of the field. The remainder of the field, if present, must contain between one and four characters, but its content is not important.
If there are date fields in your application that do not fit these criteria, you might have to make some code changes to define just the year part of the date as a date field with the DATE FORMAT clause. Some examples of these types of date formats are:
If you need to use date windowing in cases like these, you will need to add some code to isolate the year portion of the date.