Command/Ctrl + D duplicates the selected item. It happens in the Finder, and it happens everywhere in FileMaker, except the Manage Database area, where that keystroke will change a field into a Date field:
This is just plain wrong. I duplicate fields all the time, and pretty much every time I do it, I use the Command/Ctrl + D keystroke, and then have to switch the field back to whatever it was originally – Text, Number, Time, etc.
FileMaker – please fix this! Come up with some other keystroke to set a Date field, and let us duplicate fields the way we duplicate objects everywhere else – with Command/Ctrl + D.