[0] https://www.apple.com/osx/preview/images/overview_design_her...
[0] https://www.apple.com/osx/preview/images/overview_design_her...
Is the list of messages on the left another control? It's clickable, but the whole thing is visually merged with the titlebar.
This has been part of Finder and iTunes since at least 2006, at a point when it wasn't the norm for anything in GNOME2 that I can recall.
http://www.mactip.net/wp-content/uploads/2011/01/macosx_cmd_...
Or activate mission control:
http://www.iphones-apps.ru/wp-content/uploads/2013/12/Screen...
Mission Control overlays the icon and title.
In general the apps seem to be visually distinct and people aren't identifying them by titles anyway:
http://images.apple.com/osx/preview/images/overview_design_h...
Let me know if I misread your question.
For instance it would work if one could drag any area of a window that doesn't react to a click (like the white space between the bubbles in the chat window). Or additional gestures to easily rearrange/move the windows, something like three finger scroll make the window follow the fingers instead of back/forward.
With the half-exception of Safari [which had the 'fold heirarchy'], the apps that have lost the standard title bar never had these features, and what has been removed is simply the restating things visible in the menu-bar and source list.