Error while running event Kux-SlimInserters::on_built_entity (ID 6)
Unknown entity name: stack-filter-slim-inserter_part-bslim-inserter_part-b
stack traceback:
[C]: in function 'create_entity'
Kux-SlimInserters/events/on_built_entity.lua:48: in function <Kux-SlimInserters/events/on_built_entity.lua:8>

Steps to reproduce the crash:
1. Place a slim inserter and then place another slim inserter to create a Dual Inserter.
2. Right-click to delete the Dual Inserter, then press Ctrl+Z to undo, restoring a small slim inserter.
3. Place another slim inserter on this small slim inserter, and the game will crash.

Thank you very much for investigating this.
The Ctrl+Z case ist not yet implemented, but I will do this now.

EDIT:
The best way for the Undo feature would be to restore both inserters, but unfortunately at this time I have no no information about which one that was.
a) I could implement a queue for removed inserters, but this could be complcated and raises further questions, how many step backward should I remember, how do indentify the the deleted inserter, because removed entities have no unit_number....
b) I could suppress undo so that the restored single inverter ghost is removed immediately.

2.0.6 undo disabled, solution a) need more time...

Thanks for the detailed explanation. I'm not familiar with the code, so I can't offer a solution. Also, I feel that this undo action may not be common, but as long as it prevents the game from crashing, it's good enough.