The current crop of CC app interfaces give no visual indication that an application frame is active if it doesn't actually overlap another one on the screen. Unless the ruler is active, there is NO visual cue to tell the user that InDesign has focus, for example, and even the ruler change is non-obvious.

The problem is with the nonsensical suite-wide UI change that eliminated even the Windows title bar, which gives a very clear indication whether a window has focus. I assume some exec who flunked UX 101 has the idea that designers only work with one window at a time. Please re-educate that person.