Pin Locking in MPLAB® Code Configurator (MCC) 3.xx Versus Previous Versions
Pin locking is no longer a feature in MPLAB® Code Configurator (MCC), except for a few cases (MCLR, OSC pins). This was previously a feature in v2.xx which didn't support shareable inputs.
Starting with v3.00, MCC supports shareable inputs, so a pin cannot be locked only to one functionality. In v3.xx, MCC does not prevent you from generating code if the hardware allows it. If the code is not functional, MCC displays a warning notification but it will allow code generation.