ispLever Clasic 2.1 and below: How to avoid optimization of unconnected pins in a schematic entry on ispLever Classic?

ispLever Clasic 2.1 and below: How to avoid optimization of unconnected pins in a schematic entry on ispLever Classic?

To avoid optimization on unconnected pins in a schematic entry, click on the input/output symbol output net and edit the net attribute "preserve" or "keep" and set it to Y.