This is an idea that was mentioned in #1278 and could be part of the #1839 meta-issue...

So the idea is basically to have an additional "Place in layout" action available in the drop-button in the "Operations" column (mockup):

screen shot 2018-12-05 at 10 48 59 am

...this would pop up a dialog asking which layout to add the block to, and upon selecting a layout, would redirect to the "Manage blocks" page for the selected layout, perhaps with a "Select region" prompt?

GitHub Issue #: 
3406