It happens to me so many times that I roll the scroll wheel over some scrollable element, but the thing DOES NOT SCROLL. What's worse, something else on another part of the screen may scroll. I know ...
In Ubuntu when you rotate mouse wheel while mouse pointer is in a region (for example you can volume up or down without any click while you rotate mouse on volume icon in system trey), that region ...
On Mac OS X I can mouse over something (without clicking on it or giving it complete focus) and use the scroll wheel to scroll it. On Windows (7 at least) which I'm forced to use in my new job, it ...