(Actually, I think Omni experimented with a combination Stop/Reload button first, in 1994, between OmniWeb 0.5 and 1.0.)
This turns out to be a bad idea from a usability standpoint, because the button can change out from under you (in either direction) as the page finishes loading or starts refreshing, at which point your button click does exactly the opposite of what you wanted it to do (stopping when you wanted to reload, or loading yet again when you wanted to stop).
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Since I was here, I thought I'd also add: thanks!
(Actually, I think Omni experimented with a combination Stop/Reload button first, in 1994, between OmniWeb 0.5 and 1.0.)
This turns out to be a bad idea from a usability standpoint, because the button can change out from under you (in either direction) as the page finishes loading or starts refreshing, at which point your button click does exactly the opposite of what you wanted it to do (stopping when you wanted to reload, or loading yet again when you wanted to stop).