When placing rails, hovering over the undo button directly after placing a piece of rail resets the planner's start to the start of the previous segment that was just placed.
I would expect that hovering over the undo button does not change from where I am currently placing rails.
This happens every ...

Placing a biolab or inserting an item into it causes the lab to produce a very small but non-zero amount of pollution.
I would expect it to only produce pollution if it is active, i.e. currently researching, however, it does this even in an entirely new save with no research going on. On further ...