When zoomType is “x”, viewports of y axis will be calculated based on the dataPoints present within the zoomed region. But when zoomType is “xy”, viewports of y axis depends on the zoomed region. Because of this, you won’t be able to observe the variation in data when zoomType is “xy”. We would recommend you to try the same with zoomType “x”, which would be better as per your requirement. If that doesn’t fulfill your requirement please share some more details, so that we can look into it and help you better.