Thanks Jarmo,
Your solution (Update elements) works well, very good.
Below is further modified version to get also the slider and number boxes updating the graph.
Names Default To Here(1);
dt = Open("$SAMPLE_DATA/Big Class.jmp");
jitter = 0.2;
New Window("",
V List Box(
H List Box(
cb = Check Box(
{"Jitter enabled"},
If(cb << Get() == 1,
Report(gb)[GraphBuilderBox(1)] << Update Element(1, 1, 1, {Type("Points"), X, Y, Legend(3), Jitter("Positive Grid"), Jitter Limit(jitter)});
,
Report(gb)[GraphBuilderBox(1)] << Update Element(1, 1, 1, {Type("Points"), X, Y, Legend(3), Jitter("None")});
)
),
sb = Slider Box(0.1, 0.2, jitter,
neb << set(jitter);
If(cb << Get() == 1,
Report(gb)[GraphBuilderBox(1)] << Update Element(1, 1, 1, {Type("Points"), X, Y, Legend(3), Jitter("Positive Grid"), Jitter Limit(jitter)});
);
),
neb = Number Edit Box(
jitter,
<<setfunction(
Function({this},
jitter = this << get;
if(jitter<0.1, jitter=0.1, jitter>0.2, jitter=0.2);
sb << inval;
If(cb << Get() == 1,
Report(gb)[GraphBuilderBox(1)] << Update Element(1, 1, 1, {Type("Points"), X, Y, Legend(3), Jitter("Positive Grid"), Jitter Limit(jitter)});
);
neb << set(jitter);
)
)
)
),
gb = dt << Graph Builder(Show Control Panel(0), Variables(X(:height), Y(:weight)), Elements(Points(X, Y)));
)
);