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/