This is just an FYI for readers of the blog, not as adept at peeling the arguments of an expression.
If you need to get the row numbers (and color) of colored cells in a column of any JMP data table, Color Cells is not the 4th argument if there are other properties associated with the column.
Attached is the sample data table Big Class.jmp with column age with 2 sets of colored cells (red and blue). And below is a function that can be applied to any column with an example applied to the column :age.
CellColors = Function({colnme}, {ccol, cjsl, i, targ, clr={}, found=0},
ccol = column(current data table(), colnme);
cjsl = ccol << get script;
//show(cjsl);
for(i=1, i<=N Arg(cjsl) & found==0, i++,
targ = Arg Expr(cjsl, i);
//show(i, HeadName(targ));
if(Head Name(targ) == "Color Cells", found=1; )
);
for(i=1, i<=N Arg(targ), i++,
insert into(clr, Arg Expr(targ,i))
);
clr
);
clrList = CellColors("age");
show(clrList);