Some of you may remember the "TYPE" and "CREATOR" codes that came with all files back in pre-OS X days. Some may not. Many probably don't care. Anyway, what these codes meant was that any app could create a file (a text file, for example) that could then be opened by any other app that could open such files. Great! But, double-clicking on that file icon would automatically open the file in the original app. Even better! That's what most people would want and expect.
Some of you may know that Windows never used this approach. Some may not. Many probably don't care. Windows (and DOS, and most other OSs) simply used a three or four letter suffix to the files name, separated by a period. For example, a text file would be titled "MyGreatTreatise.txt" OK, you say. So what, you say. Well, the point is, that file now has no "owner!" Well, not exactly...behind the scenes, the OS has a database and decides what app will open which file "suffix." Problem solved, you say. Well, not exactly...
Suppose you create a text file in BBEdit (that's all an html, CSS, XML, etc.) file is, anyway. But you used BBEdit explicitly because it is designed for this purpose and has hundreds of features/functions that makes it easy and efficient. But now, when that file is double-clicked, it will be opened by whatever the
OS decides should open it! Whoa! What happened to "user-friendliness" or "user-control?"
Don't use BBEdit? How about Photoshop? Or Graphicconverter? Say you create a jpeg image. It gets a ".jpg" suffix. Now, double-click it tomorrow. Which app will open it? Probably neither PS or GC! At least not in Snow Leopard! Instead, Preview will grab it and display it! Obviously not suitable if what you wanted to do was make a few edits!
Actually, OS X prior to SL applied certain rules to files and still maintained and allowed apps to create TYPE and CREATOR codes in their files. And the OS would acknowledge their use and allow the creator app to open them. Apple has claimed that this capability was at its own discretion and could be changed at any time. Well, they did it in SL, without notice, without concern for developers and worst of all, users, IMHO.
"Inside" sources claim that "management" forced this change on "engineering." This suggests that public complaints may be more effective than the normal bug reporting process since 'engineering' must simply reply that "it works as designed."
For more detailed information, see this <
TidBITS article>. It describes a work-around that will be tedious at best and very difficult, if even possible, at worst!