I have four histograms overlaid half offset. two histograms are the FMO and two are Diagnosis &relapse sample.

I need the FMO the same colour, the Diagnosis +relapse histograms the same colour.

I can change the colour only for the first histogram that has been added to the graph and not for the others.

do you know if is possible to change the colour the rest of my histograms?

Thank you very much in advance