Factorio Forums

I initially noticed that the landfill in my inventory was not sorting properly. A deconstruction planner was splitting the stacks of landfill into two different sections, as seen in screenshot1.
After playing around a bit, I noticed that it wasn't a particular deconstruction planner. I had 2 decon planners in my inventory, and they were both able to occupy the particular slot in my inventory, but it didnt matter which one. I then deleted both of the deconstruction planners by right clicking them and clicking the trash can in the upper right corner. But the slot was still reserved for a decon planner. See screenshot2.
Now that the decon planner in the slot was more transparent, I noticed that the slot in my inventory was blue like when a slot is reserved for a particular item in a chest, or a train, or the old inventory hotbars. So I clicked the slot with Mouse3 and the reserved slot went away and my inventory returned to normal. See screenshot3.

I have no idea how I managed to reserve a slot like that in my inventory and I haven't been able to reproduce it. I suspect it's user error, but I decided to make a bug report just in case. I'm having troubles uploading my save at the moment (error parsing server response) so that is not included.

After playing around some more, it seems that I middle clicked on a random slot in my inventory and that reserved a spot for the deconstruction planner. Not a bug then, but is this intended behaviour? It seems strange that this can accidentally happen in an inventory that is set to be automatically sorted.

Yes, you can reserve arbitrary inventory slots, same as every other container with reservable slots.