Another Trick:
For lines, you can add labels and select which values will be displayed:

Together with the label, there will be the line:

one option to hide it:
adjust the color of the label (e.g. black) and use white for the line:

Names Default to Here(1);
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
Graph Builder(
Variables( X( :sex ), X( :name, Position( 1 ) ), Y( :height ) ),
Elements(
Line( X( 1 ), X( 2 ), Y, Legend( 1 ), Interval Style( "Arrow" ) ),
Bar( X( 1 ), X( 2 ), Y )
),
SendToReport(
Dispatch( {}, "400", ScaleBox,
{Legend Model(
1,
Properties(
0,
{Line Color( 2 ),
Line Label Properties(
{Max Value Label( 1 ), Label Color( "Black" ), Width( 9 )}
)}
)
)}
)
)
);