Just came across something a bit weird (to me at least). I have a MMDOM for which I had set set_only_related to true. I realised after testing that this was preventing the newly created item from appearing in the DOM because it had not been linked on creation so attempted to uncheck the Show Only Related Records checkbox - only to have it check itself and not reveal the missing item.
Fair enough, I'm assuming then that that's the intended behaviour of the flag. (is there any way to set it to checked by default but allow it to be unchecked as required?)
So I commented out the set_only_related(true) and tried again ... but the same thing happened, I unchecked the box, it thought for a moment, and then rechecked itself. I tried setting the flag to false, running /dev/build/, throwing a ?flush=1 on the admin url.... just shots in the dark really.
Then I realised I have a second MMDOM for this particular Page type/subclass on a different tab in the admin also set with set_only_related to true. When I commented out this flag too, then the original began working correctly. So the second MMDOM set_only_related appears to have been affecting the first.
Could this be a bug? The second MMDOM is attached to this Page class normally, the original one is implemented on the class via a decorator, if that makes a diff.