Furthermore, although it's a little ambiguous, you'll note that if you don't have that checkbox checked, Option-Tab will produce the same result.
<snip>
Dollars to donuts you hit an inadvertent Tab or Option-Tab while typing—thus highlighting the Submit button—then hit Return, thus effectively clicking the Submit button.
Option-tab then return (or enter) seems like the "magic" needed (as my pref has that tab feature unchecked). Funny that's never happened before in probably some 20,000 posts (including other sites) over a decade. But -- since it's at least possible things could have happened that way -- i'll just accept your theory. [it felt kinda eerie too... let's save that 'ghost in the machine' stuff for
next weekend.
]
