There is a shortcut for the extensions bar (CTRL+SHIFT+S) so it makes no sense there is not a shortcut for the messenger sidebar which is in my use much more useful. At least if it could have an auto-hide setting. The bars are useful, but just want to either hide or keyboard shortcut show/hide. It might seem small issue because you can unpin, but I would rather just beable to enable/disable via shortcut rather than go into a menu each time to pin/unpin.
From what I see, Opera seems to pride on it's shortcuts and gestures. So you should have this feature without a doubt. Have not use it for a long time because of issues before. Just come back to check it out and so far it's been a great reintroduction. But I swear, it's just those little things that will end up making the difference.
So, shortcut or auto hide please.