Confusing Colours in Stacked Charts

When I create charts colours are automatically assigned but I have no way of changing that or controlling which are assigned to which option.

I use charts to compare leads and sales stacked by leadsource (Dropdown field). But on all the charts the leadsources all have different colours which is really confusing. Each widget does have a key but naturally if you put 2 charts next to eachother and the colours all contradict it its really tricky for the end user to see quickly what the chart is showing them. Once you associate one colour with one leadsource your brain fills in the gaps and assumes the same applies on others. Would be great if you could select or control the colours for each option.