dunno if the XP or 7 can also.....

With 2 apps open, move the cursor over the "revealed" window of another app and you can scroll the underlying apps window.

I use it to compare related data from the different apps.

Yes - that's very handy. I remember first seeing this on our SGI Indigo 2 workstation, back in the mid-90's. I'm not sure when the "focus follows pointer" feature came to mac.

I never knew that it had a name.
I gather after doing some looking thru the series of tubes that it was hidden in 10.3 and added in 10.4.

That used to be one of my pet peeves in XP - even within the same window, if divided, you had to click to give focus to the other pane before you could scroll. I used a hack to make it emulate OS X. Since the video card driver debacle on my Win 7 install, I haven't even booted it but maybe I will just to see if they've finally copied that feature from Mac (not that Mac couldn't benefit from copying one or two Winblows features).

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