In my article "Snow Leopard Snubs Document Creator Codes" (6 September 2009), I described, and discussed the implications of, a change in Snow Leopard's Launch Services behavior, where double-clicking a document in the Finder ignores the creator code metadata signifying what application the document belongs to. I also complained that this change had been instituted surreptitiously, with no notification in any official Apple documentation.

Well, now the change is official. A sharp-eyed TidBITS reader has pointed out that in a recent revision (17 November 2009) of its Launch Services documentation, Apple explicitly calls out the change in a boxed note:

Note: In Mac OS X version 10.6 and later, Launch Services no longer considers file creator signatures when binding documents to applications. Launch Services ignores the creator signature when it's attached to a document. In addition, the functions LSCopyKindStringForTypeInfo and LSGetApplicationForInfo ignore the parameter containing the creator signature.

And in a later boxed note on the same page:

Note: Criterion 4a [i.e. the conflict-resolution rule that gives primacy to a document's creator code, if it has one] does not apply in Mac OS X version 10.6 and later.

Although this merely confirms what was already known by experience and experimentation, and although it has no bearing whatever on the question of the advisability of this change, it's nice to see Apple come clean at last and state the facts plainly, albeit more than two months after Snow Leopard's release.