In a browser, I use the mousewheel to pan up/down on the current page.
Frequently, I switch to a screenshot capture, and when I use the mousewheel to attempt the same operation (out of habit), I discover quickly that there is a nice "zoom" feature.
Thing is; I very rarely use anything other than 1:1 (100%) zoom when I use ScreenShot Captor so I wish I could associate wheel turns with panning up/down.