You may not change the blue line in this plot after the plot is made. You can set a line anywhere you like when you instantiate this display box, but you can't change one afterward.
Names Default To Here( 1 );
// make example
New Window( "Example",
Outline Box( "Blue Line Where I Want",
pcb = Plot Col Box( "Probability", {25, 45, 5, 10, 10, 5} )
)
);
// add line (same lower limit for all elements)
pcb << Lower( [ 5, 5, 5, 5, 5, 5 ] );