I had three surface(contour) plots on which I was using a custom colour
scheme (various greys). In order to make sure that all three had exactly the
same colour scheme, I created a blank spreadsheet and copied and pasted each
graph onto the page. When I did, the colour scheme changed! It was
different every time I pasted the graph. It looks like the fill colour
scheme was put back to automatic when I pasted. The program also chose a
different design colour scheme for each chart. I don't think this should be
happening!