It was a really recent upgrade, so I'm sure they're still working out
the bugs.  I'm just like you it's the most annoying thing in the world
(I'd six star your post if I could), so I'm sure a lot of other people
will complain about it eventually...  Give YouTube the credit that
most things are always going to not work quite right or quite the way
they planned until an idea or site revision has been around for a
little while.  The idea isn't bad, but there just has to be a tiny
little fix: just default it to OFF instead of ON and then if we want
to, we can click the editor on while watching.  It's a very
considerate short cut to stick on actually and would be perfect if it
just didn't automatically turn on.