works in:
DP3
DP4




Brave users can muck around in /System/Library/Frameworks/HIToolbox.framework/ and actually disable most of the Aqua UI by moving, deleting, or renaming the right resource file (Extras.rsrc). Log out and back in and your windows look like they did in DP2: Apple platinum appearance with window widgets in classic Mac OS positions. The application menu returns, but the Apple menu remains missing in action. Windows retain their transparent shadows. The dock is still there, but windows no longer minimize to it; they windowshade instead. The system font changes back to Charcoal. Generic file and folder icons retain the Aqua look. Classic applications remain under the control of the Mac OS 9 appearance manager.

Extras.rsrc contains resources very much like those found in classic Mac OS appearance themes. The match is good enough that classic Mac OS will accept Extras.rsrc as an appearance theme. The results are not pretty, however. Aside form the pinstriped background in some windows, it doesn't look very Aqua-ish, and it's so buggy as to be immediately useless. Menus stop working, clicks are missed, you name it. It's actually pretty difficult to even deactivate the appearance since pop-up menus no longer function.

Going in the other direction--trying to use classic Mac OS appearance themes in DP3 by replacing Extras.rsrc--has slightly better results. Interestingly, Carbon apps (like the Finder) retain most the Apple platinum appearance, while Cocoa apps pick up a few UI elements from the classic appearance theme file, most notably the look and position of the window widgets and some bits from the scroll bars. Large portions of the UI in Cocoa apps are completely blank, and bugs abound. Also, the presence of even an imposter copy of Extras.rsrc causes the minimize button to dock windows via the genie effect rather than using windowshading (which is the behavior when Extras.rsrc is totally removed).