Akane, try appending it to a list box, not the window directly. That should fix your issue.
Names Default To Here( 1 );
dt = Open( "$SAMPLE_DATA/Big Class.jmp" );
nw = New Window("Dashboard", hlb = hlistbox()); //vlistbox if you want it vertical
for(i=1, i<10, i++,
g = expr(dt << Graph Builder(
Size( 800, 800 ),
Show Control Panel( 0 ),
Variables( X( :name ), Y( :age ) ),
Elements( Points( X, Y, Legend( 5 ) ) )
));
hlb << Append(g);
);
Also, instead of calling Data Table's by name, its a better practice to store the data table reference in a variable and call that.
So....
//Bad Practice
mylist = {"name1", "name2"};
For(j = 1, j <= nitems(mylist) , j++,
prod_list = mylist[j];
Gr1 = expr (Data Table(" Rej Rate "||prod_list) << Graph Builder(
Size( 800,800 ),
//Good Practice
mylist = {dt1, dt2};
For(j = 1, j <= nitems(mylist) , j++,
dt = mylist[j];
Gr1 = expr (dt << Graph Builder(
Size( 800,800 ),