Hear that? It's a big sigh of relief from Mac users everywhere. In the latest Mac OS X 10.7 Lion Preview Developer Build, Apple has scrapped the switch/slider tabs that were borrowed UI elements from iOS.
As you can see from the image above, Apple has chosen to move away from the Aqua interface of Snow Leopard (and previous versions of OS X) and moved towards a more toned-down appearance. When Lion Developer Preview 2 was released, Apple replaced Aqua tabs with slider tabs. For example, in the second tab bar above, when the user clicked on "General," the white tab over "Privacy" would slide over to "General." This UI element can be found in many app settings in iOS (think of the familiar "ON/OFF" switches).
Many developers felt the switch tabs were confusing for users, and it seems that Apple has listened to them. In the third build, Apple has gone back to the depressed tab functionality (the last tab bar in the image above). I guess Apple found out that just because something looks cool and works well in iOS doesn't necessarily mean the UI element should be translated to the desktop.
Apple OS X Yosemite