Multiple User Defined Date Filters may be maintained to help eliminate problems with the entry of Dates.  Even without the use of Date Filters it is not possible to enter an invalid date (ie. 2/30/2018).  Date Filters are designed to eliminate wrong Month and Year problems.  Each Date Entry field may be tied to a specific Date Filter and each Date Filter is tied to the current period of a specific Calendar.  Each Date Filter definition contains variables use to compute the valid range of dates and determine what action to take if an invalid date is entered.