I'm not sure how to easily keep that hidden from tabulate as it seems to re-create it based on something (when you have too large Where statement it adds it back or something weird). You can do it with filter change handler but I would try to avoid that as much as possible (I would rather keep that Where text than start messing with those).
Names Default To Here(1);
dt = Open("$DOWNLOADS/example_DataTable.jmp");
nw = New Window("",
	Data Filter Context Box(
		H List Box(
			dt << Data Filter(Local,
				Add Filter(
					columns(:TestWk),
					Modeling Type(:TestWk, Nominal),
					Where(
						:TestWk == {19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32}
					),
					Display(:TestWk, Find(Set Text("")))
				)
			),
			gb = dt << Graph Builder(
				Size(744, 332),
				Show Control Panel(0),
				Variables(X(:TestWk), Y(:Median), Group Y(:TestStage)),
				Elements(
					Points(X, Y, Legend(8)),
					Caption Box(X, Y, Legend(10), Summary Statistic("N"))
				),
				SendToReport(Dispatch({}, "TestWk", ScaleBox, {Label Row(Show Major Grid(1))}))
			),
			tab = dt << Tabulate(
				Change Item Label(Statistics(N, "Die tested")),
				Show Control Panel(0),
				Add Table(Column Table(Statistics(N)), Row Table(Grouping Columns(:TestStage)))
			)
		)
	)
);
wait(0);
(nw << XPath("//TextBox[contains(text(), 'Where(')]")) << Visibility("Collapse");
					
				
			
			
				
	-Jarmo