I tried the example code but couldn’t stack it properly using lightningchart version 4.2.0

let chart = lightningChart().ChartXY({
        container: this.$refs.container,
      });
      chart.getDefaultAxisY().dispose();

      const axisTopY = chart.addAxisY({ iStack: 1 }).setTitle("Intensity Sum");

      const axisBottomY = chart.addAxisY({ iStack: 0 }).setTitle("Time");

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Sample code can be stacked properly
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