Destack UR5e-->next position is found when-->function get_sensorfz() is missing in dropdown list

Hey, just starting to work deeper with UR5e (SW ver 5.12.2.1101534).
Im destacking some parts. in destack command window Next position is found when–>function get_sensorfz() is missing in dropdown list. There are only 1. force () and 2.get_tcp_force(). When I use 1. it does not follow my instructions of -10N value when going towards starting pos, it tends to go through the object, and when I use 2.it does not work at all : Unsupported operand types.

Has anyone had the same issue, or has anyone did the similar program using UR5e to show me the steps. Found some on the web but always missing this destack command window data.