I have this schema behavior which is supposed to place the test_field as first field in the edit form (working) and a boolean field show_description after the description field (not working).
Depends on the behavior used. IDublincore is a compound. If it is used you need to reference it. If you use IBasic, then this.
IMO the whole IDublincore compound was a big mistake. But well, here we are...
The naming schema is in particular stupid when you need to redefine the IDublinCore with ÌMyDublinCore`.
So in the original behavior we move the show_description field after IDublinCore.description and with the new behavior we have to move for a different usecase after IMyDublinCore.description...it is hard to maintain and understand this nonsense... #sigh
Indeed, I really think the compound IDublinCore at all was a mistake. Keeping them separate behaviors would make it so much simpler. If a single field would have its distinct namespace it would help too, like plone.basic:description but I am not the one implementing this for free (insert coin).
I did not get all implementation aspects but it would make sense define everything single field (its interface and class implementation) by itself and then provide some easy functionality for building compounds. Building compounds from single fields is much easier than breaking a compound into pieces for the sake or reusability or customization.