Thanks for your PR Oleg.

I think though that the function setVisibleChartRangeAuto is not the right place for this logic: the function will then no longer (always) do what it's supposed to do: fit all items.

It was working for me. What is the right place then? Somewhere here?

if (this.firstDraw) {
    // logic for start / end options
   ...
    this.setVisibleChartRangeAuto();
}

Currenty, the function setVisibleChartRangeAuto() is only called in this if (this.firstDraw). I tested all use cases and it was fine, so I can not see any problems.

It will indeed work fine, but setVisibleChartRangeAuto is a public method which then will no longer behave as advertised.

I guess a more robust solution would be to create a new (private?) helper function for this, something like _setVisibleChartRangeInitial.