Dual Extruder colour change  

Dual Extruder colour change

I have a Geeetech A10M dual extruder mix head printer.  had it for a year now and so far I have been successfully using the Prusa Color site to make my changes between extruders on prints to get colour changes. or using 2 separate STL files

The latest PrusaSlicer says it can handle colour changes but for the A10M printer I dont get the + on layers view.  

I have also tried doing layer modifiers and I cant get it to change extruders on that either.  Its like the PrusaSlicer doesnt want me to change colours on my Dual extruder printer (all options are available on my single extruder printer).  

Even if i could get the + back on layers view and the print pauses i coudl manually flip the extruder on the printer for now until the functionality is there in the Slicer.

Anyone figured out a way to do colour switching on the latest PrusaSlicer software?

TIA

Kris