I've also noticed a problem with IB_Date when display format is:
dd/mm/yyyy
and edit mask is:
99/99/99
since the field is edited ok, and properly formatted when exited, but once re-entered, the first two digits of the year are put on the field instead of the last two. If you leave without edit it again is ok, but if you edit, for instance, the month, the date conversion generates an error.
(i.e. --> 10/12/01 is then displayed 10/12/2001. When re-entered the IB_Edit shows 10/12/20).

Thanks
Marco Menardi