Agree with previous comments on a multiselect option, going through and trying to manually select the 3rd upgrades area overall to upgrade new areas is tedious at best, possibly even a copy/paste option with the cost of the items placed as the paste cost to reuse a previous setup. Also, possibly an option to select the color you want your selection box to be for those with the older eyes, the white isnt too bad, but can also be lost a bit at points.
Editing this again, but also just realized in the demo videos, that the bounding box for the harvesters is also expandable at least it seems for the first 2? I had no idea until I off handed tried.