After 2.1.2 to 2.2.2 upgrade, get_table_options returns different array

Strange thing... We recently upgraded an instance of Omeka from 2.1.2 to 2.2.2 and found that the get_table_options() method is returning different results (the array we wanted is nested) compared to other instances that have the same code base (v2.2.2, a custom theme, and 4 new plugins). Perhaps you can shed some light on the following thoughts:

- This made me think that there may be a difference between the DB as if there was a DB update for this version jump. It appears that there was no update to the DB. Should I stop thinking DB here or is there something I'm missing?

- Here are some details from the system information page on our newly upgraded server. PHP 5.6.8; MySQL 5.5.28; PHP Extensions not found between working instances and this one are gmp and ldap; PHP Extensions running on this server but not others are gd, mysqlnd, posix, sqlite3, sysvmsg, sysvsem, sysvshm. Could it be a PHP environment issue that is causing this?

I could of course fix the result programmatically, but putting out the fires here and there could continue if there are more unseen issues related to this. I would much rather get to the bottom of why this is happening in the first place.

Thanks in advanced for any advice you may have.

get_table_options itself isn't changed, but what table are you getting the options for?

I suspect that it's the Element table. Omeka 2.2 introduces a switch that lets administrators turn on or off the Element Set headings/groupings for Elements (e.g., "Dublin Core"). If the headings are on, the Element table options are nested by Set. If the headings are off, it's a flat array.

Ah, it's most certainly is the Element table we are looking to grab. With a little bit of hunting, I was able to find the "Show Element Set Headings" option in Appearance > Settings. Turning that option off flattened that array and now things are great again.

Thank you Mr. Flatness!