Sometimes you already built a building and need a duplicate (e.g. shelter).
I often find myself clicking on an existing building and try to copy it, since I am used to from other building games.
It would be great to have a "build copy" button, that preselects the necessary building so you can just duplicate it.
in case it wasnt clear in the comments, this option already exists. As described, it's the "SHIFT" button when you mouseover a building you can build multiple of (so not main hearth, main warehouse, architect office, etc), and dont have any other building selected
shift when you are hovering over the building but don't have a building selected