As long as you know the maximum number of plots you might have, you should be able to set up the colors for all the plots ahead of time. You could do this manually, but if there are a large number of plots, you'll probably still want to do the setup programatically. To start, you have to init the number of plots in the graph or chart; otherwise the number of plots is defined by the data. To do this, view the plot legend. For a large number of plots, right click on the plot legend and select the index control so you can manipulate it like an array. You can put the index ahead to "99" and click on the control to init the plot array with 100 elements. Now you can set the color for all 100 plots programatically. Once the setup is done you can copy the control to another VI and/or save the VI / Control with all the properties as they are, so you won't have to do it on each run of the actual program.
