This question is on how to use an OSX program and would seem ideal for apple.se.
However, the only migration options are meta, superuser, tex, dba and sharepoint, none of which are at all suitable.
How do I migrate to apple.stackexchange.com (not on the list)
In such cases, you can raise a flag and use the "other" option with a reasonable reason.
However in this particular case, I dont see a reason to migrate this question. It is on-topic for Stack Overflow as it is related to programming and IDE.
From Help Center:
What topics can I ask about here?
- software tools commonly used by programmers
First, it's perfectly on topic for Stack Overflow, as it's about a tool that is commonly used by programmers. Questions about editors (in the context of using them for programming) are generally a fine fit for Stack Overflow.
As for migration paths, there's very little overlap between Stack Overflow and Ask Different, therefore establishing a conduit between the two doesn't really make sense. It's very unlikely that questions asked on Stack Overflow would conceivably get better answers on Ask Different, with the possible exception of some very Apple flavored development setups. Even then, those tend to get pretty good answers on SO.
If you ever come across a question that definitely belongs on another site that isn't in the migration paths (meaning, the question author is likely to get MUCH better answers there), then you can flag it for moderator attention and ask them to see if the migration would be in order. It would then be up to them to agree, and then send it over.
Xcode is a developer tool as far as I can tell. Questions about such developer tools like IDEs are on-topic on SO, so they should not be migrated in the first place.
In cases where the migration is actually warranted and the post off-topic on SO, just flag as "other" and explain which site it should be sent to. Diamond moderators can migrate to any site in the network. One exception are older questions, don't bother flagging questions older than 60 days as even mods can't migrate those.