Strictly speaking, the explanation in the active.help is no longer correct as it speaks of being active in relation to the title-bar being highlighted. Instead of the title-bar it's now the toolbar that takes this role. Or, with All Windows Active on MacOsX, clicking in the background window will (while remaining in the background) activate it's toolbar and not the titlebar (as expected); active reports 1.
Speaking of related stuff, very much I miss (and I cannot decide whether it's an improvement or not) being able to make frontmost a window by cmd-clicking in it, without having to hover all the way to the titlebar. I realize that with 1000 persons working with Max, 1000 modes of dealing with it are developed.