The action buttons to logout or lock the screen are very small when they are displayed vertical.
Are they smaller than they could be? They should get half of the panel size minus the button borders. I think this depends on the theme as well.
Going to close this when the new panel is merged. I don't see a difference between the vertical and horizontal panel (ie. no icon resizes).
Devel branch has been merged in master. A 4.7.0 release will follow soon. If you think this bug is not fixed? Feel free to reopen the bug.