I've found an issue with PlotWindow and callbacks. The example script I have included adds velocity vectors on top of a slice:
Later on in the script, I try to resize the plot, but I get this error:
This is because the field list now includes x-velocity and y-velocity, but there are not any plots corresponding to these fields in the list. I figure that the answer to this is to retain some sort of field list that corresponds to the fields that are actually being plotted in the colorscale, but I figured before I just went in and dropped it in somewhere I'd ask for opinions as to where it should go.