You can right click on the graph and select Customize, and in there you can add the code to place the marker where you want it.
Below are a couple of ways you can do it just through scripting
Names Default To Here( 1 );
dt = Open( "$SAMPLE_DATA/big class.jmp" );
Graph Builder(
Size( 528, 456 ),
Show Control Panel( 0 ),
Variables( X( :weight ), Y( :height ) ),
Elements( Line( X, Y, Legend( 8 ) ) ),
SendToReport(
Dispatch(
{},
"Graph Builder",
FrameBox,
{Add Graphics Script(
2,
Description( "" ),
Marker Size( 9 );
Pen Color( "Black" );
Marker( Marker State( 1 ), [113], [69] );
), Grid Line Order( 1 ), Reference Line Order( 3 ),
DispatchSeg(
TopSeg( 1 ),
{Set Script(
Marker Size( 9 );
Pen Color( "Black" );
Marker( Marker State( 1 ), [113], [69] );
)}
)}
)
)
);
// or
gb = dt << Graph Builder(
Size( 528, 456 ),
Show Control Panel( 0 ),
Variables( X( :weight ), Y( :height ) ),
Elements( Line( X, Y, Legend( 8 ) ) )
);
Report( gb )[FrameBox( 1 )] << Add Graphics Script(
Marker Size( 9 );
Pen Color( "Black" );
Marker( Marker State( 1 ), [113], [69] );
);
Jim