I think Mr. M means the following: In the figure GUI, after one has worked hard to generate a nice figure by combining the outputs of various scripts via copy + paste, how can one change the order of the legend?
In earlier versions of MATLAB, one could achieve this by cutting and repasting traces. They would then reappear at the bottom of the legend. So you would take the trace you want to be second, cut and paste it, then do the same for the third, all the way to the Nth, and then the legend would have the desired order. Now it is no longer possible to do this. The figure somehow remembers the position of the trace before it was cut.
But there is a WORK-AROUND! Simply cut the trace, paste it in onto a different axis of a different figure, then cut that trace and paste it back onto the original figure. This stymies matlab's attempt to remember the order of the trace and puts it onto the bottom of the legend.