Adding Custom color to CFS - issue with filament load / retract from correct slot on same color

Is there a way to add a custom color to CFS setup ?
i have an issue with transparent filament which does not have any color. and there is no option for blank to be picked.
have thought that ill just pick white and remember in which slot its loaded but noticed one thing.
if i have white PETG loaded in slot 1 and transparent in slot 4 and want to print with transparent filament but last print was done with white from slot 1, printer does not always swap it but continues with the one which was loaded (slot 1) but at the end of print it wants to retract from slot 4 (the one from which print run initially) what is causing retract issues as it pulls roll and doesn’t see any movement on filament sensor so printer thinks filament is jammed.