Factorio Forums

When objects have been manually replaced to another tier, the first use of Undo command marks them for deletion, and the second puts the ghosts of the objects that were before the replacement.
But when they have been replaced by Upgrade planner, the Undo command only deletes the new objects, but does not return the previous one.

It isn't technically a bug report, as fast replace/upgrade usage was just not included in undo since the beginning.
But, it makes sense to include it, so the upgrade/fast replace actions are now (for the 1.1 release) supported by the undo.

I am sorry. I didn't know where i should to post this.
But thank you.