Hidden connection pins are generally not allowed for schematic symbols. Any connection point must be visible, otherwise unexpected net connections can occur.
Hidden power pins are also not allowed.
Unused NC pins can be set to invisible. In this case the electrical type must be
Not Connected. The end of the pin should lie on the symbols outline box to prevent unwanted connections to the invisible pin (see screenshot below).
Invisible pins may be used in a pin stack to allow one-to-many connections. Refer to the requirements for pin stacking