The block move and block ellipsis buttons both have 20x20 clickable areas - this feels a little easy to miss, particularly with the hover visual feedback being quite subtle. For comparison, the similar buttons in Dropbox Paper have a 24x24 icon, with a 32x32 clickable area. I suspect this will become more necessary when 3044 is implemented, as having UI that disappears if you twitch too much is wildly frustrating. Also mentioned here: https://wordpress.org/support/topic/tested-for-a-couple-hours-today-feedback/