Mining tower areas can be modified by pulling the corner vertices.
If two adjacent tower areas have the same vertices, then pulling it should modify both tower areas. It's annoying to have to do an area modification twice.

This is a particularly annoying one. If I accidentaly pull the area of one tower into the other, I get no notification like I get with mining area outside of tower range. I just notice it when my precious dirt is dumped into the ocean.

We should get an error notification of tower areas are overlapping.