So if I understand correctly, the zoom reset button only goes back to the last call to stockchart.render().
This would seem to work against the ability to do live updates as suggested by your example:
https://canvasjs.com/docs/charts/how-to/live-updating-javascript-charts-json-api-ajax/
The moment a live update comes in, the end user looses the ability to reset their zoom to anything before the last update (due to the stockchart.render() call).
Consequently, I would like to make a feature request that the zoom reset button’s history extend beyond the last call to stockchart.render() so that resetting the zoom actually works with live updates.