ETC Element- fixture parameters.

I have a bank of CYC Floods that are Red, Green, Blue, Yellow.

I have this set up as an LED fixture so that i can use the colour picker- Mainly for the less experienced that don't understand that they are separate dimmers.

with this fixture- whenever i select a colour on the colour picker I can't get Yellow to change. it seems to try change it to and RGB fixture and won't ever do anything with the yellow. if i select yellow in the live table i can get it to change but never when i do anything with the colour picker. is there a way round this? or should i just revert this back to being 4 dimmers and have the task of trying to explain this to everybody who uses the desk. (its a school so many people have little experience)

Many thanks in advance for any advice/similar experiences shared.