private void OnSceneGUI()
{
    var graph = (GridGraph)target;
        
    float size = HandleUtility.GetHandleSize(graph.transform.position) * 5f;
    float snap = 0.1f;
        
    EditorGUI.BeginChangeCheck();
    Handles.color = Color.yellow;
    float plusX = Handles.ScaleValueHandle(graph.transform.localScale.x / 2,
        graph.transform.position + graph.transform.right * graph.transform.localScale.x / 2, 		  
        Quaternion.LookRotation(graph.transform.right), size, Handles.ArrowHandleCap, snap);
    if (EditorGUI.EndChangeCheck())
    {
        Undo.RecordObject(graph, "Scaling graph.");
        float diff = plusX - graph.transform.localScale.x / 2;
        graph.transform.position += graph.transform.right * diff;
        graph.transform.localScale += Vector3.right * diff * 2;
    }
}