I was wondering, if I am doing something wrong or is there something missing.

F405WMN with Delta mixer and one motor by default sets motor output to S1, S2 is empty (the same timer) S3 and S4 are for elevons.
I want to use S5 to control my ESC so what I do is I add in mixer tab another output as "stabilised throttle".

I need to keep the motor mixer on S1 because if I delete it then elevons are moved to S1/S2 and stabilised throttle goes on S3.

When I arm the plane and move my throttle stick the motor runs, so this is fine here.
However in the configurator tab where we can use configurator to run the motor with the slider I can't run my motor connected to S5.

Is this some kind of bug, maybe some "link" missing in programming? Or should I do something else.
I do need the ESC to be on S5, basically as I want it to be on Dupont connectors and not soldered to S1 pads for ease of disconnection if needed.