You have spent all morning trying to figure out why items – that you know should show up for purchasing – does not show up in the planning worksheet. No matter what you select in the planning parameters on the Item Card is ignored by the planning.
You might have run into one of the small peculiarities of Dynamics NAV 2013 to 2015. The situation occurs if you have selected Location Mandatory on the Inventory Setup card and you are not using the manufacturing module.