Somehow visualize hidden/overlapping blocks #42
Description
Need to check if an always-on and realtime visualization is too expensive.
Options:
- red bar/exclamation mark at the top of sections that have hidden blocks
- make block outline faintly appear through overlapping blocks
- manually executed tool that finds overlaps (how to display/fix results?)
Need to think about if partially overlapping should be highlighted as well, I think it should. Maybe "if at least one boundary is invisible" is a good criteria (it eliminates the obviously desired case of a small highlight in a larger background block).