I was not able to correct your issue using Bivariate, however, it works correctly using Graph Builder.
names default to here( 1 );
dt = current data table();
// Set selected rows' colors
dt << Select Where( :Z == 1 ) << Colors( "Dark Red" );
dt << Select Where( :Z == 2 ) << Colors( "Dark Green" );
dt << Select Where( :Z == 3 ) << Colors( "Dark Blue" );
dt << Select All Rows << Markers( "FilledSquare" );
Graph Builder(
Size( 531, 456 ),
Show Control Panel( 0 ),
Variables( X( :X ), Y( :Y ), Overlay( :Z ) ),
Elements( Points( X, Y, Legend( 3 ) ) ),
SendToReport(
Dispatch(
{},
"X",
ScaleBox,
{Min( 0.92068931615959 ), Max( 2.08769739976682 ), Inc( 0.2 ),
Minor Ticks( 1 )}
),
Dispatch(
{},
"Y",
ScaleBox,
{Min( 0.866326530612245 ), Max( 2.12682788421491 ), Inc( 0.2 ),
Minor Ticks( 0 )}
),
Dispatch(
{},
"400",
ScaleBox,
{Legend Model(
3,
Properties( 0, {Marker Size( 6 )}, Item ID( "1", 1 ) ),
Properties( 1, {Marker Size( 6 )}, Item ID( "2", 1 ) ),
Properties( 2, {Marker Size( 6 )}, Item ID( "3", 1 ) )
)}
)
)
)
Jim