The mod Smart Inserters (2.0.12) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Smart_Inserters::on_gui_opened (ID 95)
Smart_Inserters/scripts/selector_gui.lua:26: attempt to index field 'items_to_place_this' (a nil value)
stack traceback:
Smart_Inserters/scripts/selector_gui.lua:26: in function 'generate_slim_inserter_grid'
Smart_Inserters/scripts/selector_gui.lua:221: in function 'create_pickup_drop_editor'
Smart_Inserters/scripts/selector_gui.lua:337: in function 'create'
Smart_Inserters/control.lua:64: in function <Smart_Inserters/control.lua:58>

spage-age, controller_type=editor, space-plattform, built: furnace and select
I'll try to reproduce that again

Did you build a furnace? not a slim inserter?

yes, i was also surprised. i wanted to build a furnace in this case. i can no longer reproduce it.
but regardless of what i wanted to do. there was a crash that wasn't supposed to happen ;-)
i finally made it to the first space platform to play
from now on I will test slim inserter and smart linked chest on the platform.
I was able to set other slim inserters there before without any problems.

The strange part is that to get to that function it had to pass the "is_inserter" function on control.lua:60.

https://github.com/Wip-Sama/Smart_Inserters/blob/b6a2c47c27ff617d57d194d1bb15530951aa3dd5/scripts/inserter_functions.lua#L126C1-L129C4

I can probably find some more checks before getting to that point but IDK I will need to try and reproduce it.

I will watch it. or the bugs crawl alone