Perusing the Apple Discussions board several weeks ago, I was surprised (and, okay, pleased) to find my name, and one of my books, mentioned in passing. But the thread was talking about how the font auto-activation feature wasn't working for TextEdit in Mac OS X 10.5.2, and the mention was "interestingly, the book by Sharon Zardetto, 'Take Control of Fonts in Leopard,' has a section on auto activation, and there is no suggestion that it doesn't work." And that's true: except for stipulated problems with Microsoft Word 2004, I didn't say, or even intimate, that auto activation might not work - because it worked when I wrote the book. Since the Mac OS X 10.5.2 update, however, its performance is patchy.
Fair warning: this article only describes the font auto-activation problem; there's no solution available. When I started writing this article, I hoped that Mac OS X 10.5.3 would provide a solution, but that has not turned out to be the case.
Not-so-auto Activation -- The auto-activation feature in Leopard's Font Book (turned on and off in its preferences) checks a document as you open it; if the document uses a font that's not currently active, you get a dialog asking if you'd like it activated. The extra-special aspect of this feature is that you don't need the font in Font Book at all - if the font is anywhere on an attached drive, Font Book finds it and offers to activate it for you; the font stays available inside the application until you quit it. This is invaluable for people who use different fonts for different projects but don't want them all on, or even installed in Font Book waiting for manual activation; it used to be a feature only in third-party font management software.
In Mac OS X 10.5.2 and 10.5.3, however, this feature just doesn't work. Look for the auto-activation notice for a Pages or Keynote document, and you get the insipid "Some warnings occurred. Would you like to review them now?" dialog, and the "review" unhelpfully states that a font is missing. In TextEdit, you don't get even that dialog: the document just opens with the default font substituted. As if to make up for its lackadaisical behavior when opening a document with a missing font, TextEdit occasionally overcompensates. Leave its Font panel open, disable a font in Font Book, move back into TextEdit, and you might get an auto-activation dialog asking permission to activate the font. And you're not allowed to refuse: click the Don't Allow button, and you get the dialog again. And again. It doesn't give up until you give in and click Allow.
Word 2004 never played well with Font Book's auto-activation feature, but now the feature doesn't want to come out and play at all. Word 2008's relationship with auto-activation is squirrelly at best, and schizophrenic at worst, with auto-activation dialogs sometimes popping up while the program is starting up, or well after you've opened a document that doesn't even contain the font you're being queried about. InDesign CS3 does what it did under earlier versions of Leopard: it ignores Font Book's auto-activation and reports missing fonts in its own way.
That said, we can't complain about the third-party products that don't work with auto-activation, since there's obviously something broken on the Font Book end of things.
But is it a Font Book problem, or a Mac OS X problem? Since there's no way to control font auto-activation except through Font Book, I can't experimentally confirm or deny which is the culprit. (Third-party font managers have offered auto-activation in versions of Mac OS X before Leopard, so it's unlikely they're hooking into any system component of Leopard to perform the trick.) So, I don't know which is the problem, but I don't think the distinction makes a lick of difference to users. The special auto-activation feature that made Leopard's native font handling a boon to fontophiles who don't otherwise need a more full-featured font management utility has gone missing through two Leopard updates now, and might push some of us back to a non-Apple solution if it doesn't return soon. We're not waiting for Snow Leopard, Apple.