[dchest]

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).

[vtail]

XCode 4, though it happened even before 10.7

[dchest]

Xcode had [mostly] single window mode since 2.0 or so. It wasn't default, though, and Interface Builder was a separate application.

[dchest]

For downvoters: Xcode 3 > Preferences > General.

Layout: All-In-One

"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".

http://i.imgur.com/uW3SI.png

[bonch]

It wasn't a true single window mode; there were still secondary windows, and Interface Builder was not integrated.

[bonch]

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.