I found this by letting JMP first script it for me. I first modified the line width from Customize menu
and then got the script for Graph Builder to Clipboard
Graph Builder(
Variables(Shape(:Country)),
Elements(Map Shapes(Legend(10))),
SendToReport(
Dispatch(
{},
"Graph Builder",
FrameBox,
{DispatchSeg(Shape Seg(1), {Line Width(11)})}
)
)
)
From there I knew I can use Find Seg to get reference to Shape Seg(1) and finally I just tried if << Line Width() would work. Of course after knowing that you are supposed to look for Shape Seg instead of Graph Builder, you can also search for that in Scripting Index.
-Jarmo