Another option might be to search for the text box(es):
(fp_win<< XPath("//TextBox[contains(text(),'Where')]")) << delete box();
Or, in an example:
Names default to here(1);
dt = Open("$Sample_data/iris.jmp");
gb = dt << Graph Builder(
Size( 534, 456 ),
Show Control Panel( 0 ),
Variables( X( :Sepal length ), Y( :Species ) ),
Elements( Line( X, Y, Legend( 6 ), Error Interval( "Range" ) ) ),
Local Data Filter(
Add Filter(
columns( :Petal length ),
Where( :Petal length >= 1 & :Petal length <= 6.4083 )
)
),
SendToReport(
Dispatch( {}, "Graph Builder", FrameBox, {Reference Line Order( 3 )} )
)
);
(gb << XPath("//TextBox[contains(text(),'Where')]")) << delete box();