Possible to change some line widths in an roccomp graph?

[Sara Hansen]

I want to make one of my lines smaller in a roccomp graph. I have trined lwidth-option, but it is not allowed. Below is my code for the graph:

roccomp truth group1 group2 group3, graph summary legend(size(small))

I hope one of you can help

[Andrew Musau]

E.g., plot 2

plot2opts(lwidth(2))