The best one yet !

I was relying on the EditorsKit plugin to display the borders, but this one is better, easier to see ALL the borders and the hover effect is the icing on the cake.

The only thing I changed was the color of the hover border from black to green, simply because it is more usual to have a black background in a container block, like the Cover or Group blocks, as oppose to a green background.

Thanks a lot for this !