In the wxterminal, it is not possible to identify which curves are toggled on and which are toggled off when looking at the key/legend. I frequently plot 10+ curves, some with the same color, turn them all off and only select individual ones.
For instance, when I then want to send the plot to someone else, that person has no idea which of the 'red' key titles corresponds to the plotted 'red' curve.
The attached image illustrates the problem better than words can. Try to identify which legend matches the two plotted curves.