One requires changing the active window to be Window's "Focus" to accept input - the other would reqiure the "Mouse cursor" to just be over a window for it to accept input. (changing focus without chaning focus)
The later could be used for like mouseover healing or something - although I don't know if WoW itself will work that way.
Okay, that's Active Window Tracking. Like I just said somewhere ellse, I'll add a toggle for that to the next build.
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