in what file can I find the line
[date date-222 20/ date-format:mm/dd/yy year-range:2012-2020 first-day:1 watermark "Date"]
When you are creating or editing the form, you have 2 columns, the one at your left is where you edit the properties of each item on your form, the one at you left the fields and elements in your form, there you can find what you are looking form, see my example below:
.... Preferred Time for Showing:<br />
[select* PreferredTimeforShowing include_blank "Morning" "Afternoon" "Evening"]
[date date-222 20/ date-format:mm/dd/yy year-range:2012-2020 first-day:1 "Date"] ....
However as you mentioned, this thing is not working and seems like there's no solution for this, not sure what to do.....