improve moving block(s) to empty container

Hi,
while building a new site, we sometimes need to rearrange our container order. So we create a new container and drop some blocks into it using the blue line.

But this proves to be quite difficult sometimes, because these lines are rather small horizontally. And you drop your blocks in the wrong container from time to time, if 2 containers are nearby.

Would it make sense to not only show the line of a container, but also its border to clearify which container is getting focused? This could be a customizable feature of course.

Thanks and cheers.