This is a VERY frustrating limitation to FileMaker value lists. I can suggest a few work arounds:
Set up two fields, your value list text field can enter the month name and a different field uses the month name selected from the value list and entered into the text field to auto-enter the month number. Your value list can then be a custom value list that lists the month names in correct order.
Use a selection portal instead of a value list. The portal displays your months, but sorts by month number. The fields in the portal row are set up as a button that performs a script to enter the month number. To save on layout space, this selection portal can be put inside a popover in FileMaker 13 or in a modal dialog window in older versions. (Takes a script to open the dialog window.)
To see more examples of what to do when a FileMaker Value list simply won't cut it, see "Adventures in FileMaking - Enhanced Value Selection".
Thank you so much! I spent -hours- looking for a solution (even related tables, but a value list doesn't pay attention to the sorting order there). I'll look that over, and would it be helpful if I post the solution I choose (find)?
You never know. Since I created the demo file, it's unlikely to help me, but you never know who else might read this thread in search of an answer.
Okay, I had to opt for the 'second field with spaces' workaround.
But to get the Month name back to a number, I had to create a calculation field that measured 'cases' of month name - between two languages (I'm developing in English, but the end result (use) will be in French), meaning 24 - but it works in the end. I really wish we could get a "'show only second field, but sort by first' option for value lists" request to the Filemaker developers.
For a bit of added clarity, my goal (attained, thanks to you!) was to create an 'analytics period' for billing with dropdown menu month/year choices, recompiled into two 'start date' and 'end date' fields (not in the layout).
I've submitted my own "wishlist" to FileMaker Inc. and upgrading its value list features was part of that list. We can spend a lot of time complaining about what FileMaker can't do for us or we can spend the same time and energy figuring out how to get the job done with what FileMaker can do. I'd rather devote the majority of my time and energy to the latter.