When I paste data into JMP the date is formatted MM/DD/YYYY which has caused plotting issues with the 09 / 10 changeover. Is there a way to change the default date formatting in JMP to YYYY.MM.DD. Universally not just for that specific table?
I think on a new column, JMP tries to make the best format guess it could. I entered a date in the form YYYY/MM/DD and paste that into a new column, the format was set correctly. I wonder if the first date in your list was ambiguous, something like 01/01/2010. In that case, JMP turns that into MM/DD/YYYY.
Where does the data come from that you are pasting into JMP. What does it look like in the source? What sort of plotting issues are you seeing? Dates in format MM/DD/YYYY should sort properly across years in JMP.