Ian's method is what I do. I also use the customize menu (right click "Customize...") to change the colors of the curves. Once you select the Customize you will get a dialog box. On the left is list and for a ROC curve in that list will be a couple of items called "Script". The first might look like:
Pen Color( 9 );
Y Function( XTemp + 0.511242728306672, XTemp );
I will often delete that one as it is what draws the "yellow" line on the ROC curve that I am generally not interested in. The second will start like:
Line(
[0, 0.0007097232079489, 0.0014194464158978, 0.0014194464158978,
0.0014194464158978,
If you click on the "Templates" menu and select "Pen Color" you will get
Pen Color("blue");Line(
[0, 0.0007097232079489,
Then you can change the color to any color you want (use a color word with the quotes or use a # without the quotes, I usually just pick a word: red, green, purple, orange, etc.).