public void Arrange(GridRange range, GridLayoutModel model)
{
var start = range.Start;
var first = model.Touch(First.ElementKey);
model.Arrange(First, start.To(start + first.LastMeasure).Clip(range));
start += first.LastMeasure.Row.AsVector;
var second = model.Touch(Second.ElementKey);
model.Arrange(Second, start.To(start + second.LastMeasure).Clip(range));
}