You are sweeping out a red area to demolish, during the process a research completes and the research window pops up. You can dismiss the research window, but you are locked into [sweeping red] demolish mode.
You can’t demolish, you can’t hit the esc key to get out, and the effect is persistent between saves, so doing a save and re-load, won’t help you.
The only way to get out, is to open the build menu and select demolish again. Anything on your factory floor in the red zone when you do that, is wiped out. Likely, something you didn’t want to demolish.
- Start a research.
- Sweep out a red demolish zone with your finger holding the trigger to keep the red active, and wait.
- When research completes, dismiss the research popup. (Upgrading slots may or may not, make a difference. IDK) You are stuck with permanent red zone.
Suggestion: Aside from fixing the bug, it’s not a good idea to allow the red demolish zone to be preserved in the save file. At least then, you can always restore your last auto-save.