Keep asking:
Now I open the data table with JSL and import X, Y factors and validation columns, but the decision tree is not operated here. In this state, how to open the "Minimum Size Split" box of the decision tree with JSL?
I know I can set the Minimum frational portion with JSL, but I don't want to do that and just ask to open the "Minimum Size Split" box of the decision tree with JSL.Thank you very much!

obj = Open( "$SAMPLE_DATA/Boston Housing.jmp" ) <<
Partition(
Y( :mvalue ),
X(
:crim,:zn,:indus,:chas,:nox,:rooms,:age,:distance,:radial,:tax,:pt,:b,:lstat
),
Validation Portion( 0.3 ),
);