Get Vertical aligned nodes in tree layout

hi team,

I want to align first level child nodes in a vertical manner but got a issue in first level of tree. As you can see in below diagram:

In this diagram, I want first level child alignment as same as n-level child alignment(Vertically aligned)
here is the pictorial representation of what I want to do in my diagram:-

here is layout code:-



            treeStyle: go.TreeLayout.StyleRootOnly,

            arrangement: go.TreeLayout.ArrangementHorizontal,

            angle: 90,          

            alternateAngle: 0,

            alternateLayerSpacing: 35,

            alternateAlignment: go.TreeLayout.AlignmentStart,

            alternateNodeIndent: 10,

            alternateNodeIndentPastParent: 1.0,

            alternateNodeSpacing: 10,

            alternateLayerSpacingParentOverlap: 1.0,

            alternatePortSpot: new go.Spot(0.01, 1, 10, 0),

            alternateChildPortSpot: go.Spot.Left


So suggest me some properties manipulation in tree layout through which I can achieve my expected output (First level child nodes vertically aligned)

Don’t set TreeLayout.treeStyle, and then don’t use the “alternate…” properties but use the regular (non-alternate) properties instead.