There are windows on macs, but it appears Macs are going away from them with the full screen apps. Look at all of Apple's apps - they're all going single window. Document based apps can still have multiple windows, but everything is self contained.
I don't see what's changed in 10.7 regarding windows. Can you point the app that had multiple windows, but moved to something else?
But you're right that you can avoid using multiple windows in the app if it's good for usability. My point is that currently it's not possible to have two repositories opened simultaneously; especially since on OS X it's difficult to open two instances of the same application.
(As an example, in Mail you have previews in a single window, but you can also double-click the message to open it in a separate window).
"This layout provides virtually all operations within a single window, such as editing files and project content, filtering in the detail view, viewing the build results and build log, and debugging".
I don't see what's changed in 10.7 regarding windows. Can you point the app that had multiple windows, but moved to something else?
Other than the APIs for fullscreen support, there's little that can be said without violating NDA. Other Apple applications have gone single-window over the years; Logic merged its windows two major versions ago, and Final Cut Pro X just did the same.
Steve Jobs has always preferred single windows. Before OS X 1.0, the toolbar button was instead a toggle for single window mode.
