Chrome and overlapping windows
Chrome has this interesting behavior I can't exactly reproduce. I haven't tried very hard, I am sure there is a pattern. What it does is, when it's on top of another window, if you click on the body of the window underneath, it won't bring it to the forefront. I mean, if you select a control, or anything, it will do it, but Chrome remains on top. It does this until you click somewhere on the frame of the window underneath, and then it comes to the forefront and Chrome goes under. I can't recall any other application doing this.
iTunes does something unusual too, not the same, but non-standard. If it doesn't have focus, it takes 2 clicks to get it to do what you want: one click to make it the forefront app, and another one on the action or control you want to activate it. Windows apps in general do no behave in this way, a single click gets you the app to the forefront, and if you clicked on a ui control or action, it performs it.

