Thank you, now everything is clear. You're using slip_mode in your controller mapping, and pad4 has "slip"."
Create a pad and copy everything from pad4. Instead of "slip" type "slip_mode" there. It will work just like on the controller.
I also checked the mallmuzik file repository, and there's a file in the mappings folder for the MixTrack Pro FX controller, so you can use it for future modifications.
And here's the description of the slip modes from the VDJ website:
slip_mode
While in slip mode, during loops hotcues or scratch, the play cursor will keep moving unaffected, and will resume from there after release
slip
activate or deactivate a global slip mode, that will save the position on "slip on" and resume where it should have been if untouched on "slip off", letting you do any scratch/loop/effect/etc in between
Good luck and let me know if it worked, Zenek