Just after I completed building burner inserter, a drill and two belts, the robot drove south and then the game crashed with this stack.

The version is the last experimental (0.17.53)

465.580 Error MainLoop.cpp:1183: Exception at tick 4265993: The scenario level caused a non-recoverable error ...

How do I clear a field from the new toolbar in 0.17? Tried almost everything, including the deconstruction planner, and am still stuck with three red underground belt items which I cannot get rid of.