I cannot understand the behavior of complexplot in the following...
Suppose you do the following:
> f := (x,y) -> sin(x+I);
> g := (x,y) -> cos(x+I);
> complexplot([f(x,y), g(x,y)],x=-2..2,y=-2..2,color=[red,green]);
This will plot two functions in red and green respectively.
Now, I redefine the functions to return a constant:
> f := (x,y) -> sin(I);