Sometimes when I use Ctrl+Z to undo I get an error and im thrown out of my current game, though not out of Factorio.
The mod Ore-ganizer (0.9.9) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event ore-ganizer::on_undo_applied (ID 188)
ore-ganizer/control.lua:1086: attempt to index field 'target' (a nil value)
stack traceback:
ore-ganizer/control.lua:1086: in function <ore-ganizer/control.lua:1080