Hi!
I needed to replace rail with whatever to move a blueprinted station half a rail up, so I put rail in the "from" slot and yellow belt in the "to" slot. Swap worked fine, but the next time I opened the Foreman GUI I got an empty blueprint list an error about not finding item "straight rail".
Hotfix to get the blueprints back is just to insert some other item into the "from" slot.
