On macOS, the date navigation area of a field set with a control style of drop-down calendar is unable to display a four digit year, regardless of system settings. Asked at DevCon 2017 in Phoenix at the FMI tech support booth, and received email response a couple weeks later that there is indeed no way to use the system's date setting to make this a four digit year via the system settings on Macintosh.
Rationale for idea: time savings and efficiency, consistency between Windows and Mac, conformity with most modern interfaces with respect to display of years.
For dates whose year component's rightmost two digits are less than 32 when glancing at only the navigation area of the drop-down calendar, it isn't immediately intuitive if the number after the month name is referring to a date within a month or referencing the year. Not really a big deal for years after xx31, but for years between xx01 and xx31 its a bit antiquated form of notation. In fact, not really a big deal at all, more of a "nice to have" feature.
Thanks so much for your consideration.
FM17 Mojave drop-down calendar showing "October 16"
FM17 Windows 10 drop-down calendar showing "October 2016"