[Bug] Scatter series on different zlevels re render when not needed

[ddegan]

Version

6.0.0

Link to Minimal Reproduction

https://codepen.io/ddegan/pen/myVOEJV?editors=0011

Steps to Reproduce

1. Open the provided link
2. Click on one of the scatter points.
3. Observe that the large dataset is re-render

Current Behavior

Setting a series that is placed on a different zlevel just create a new canvas object but then all the points are re-rendered when the series with a single point is changed

Expected Behavior

just the changed series with a different zlevel should be rerendered

Environment

- OS: Windows 11 pro
- Browser: Chrome 140.0.7339.208

Any additional comments?

Don't know if I'm doing something wrong or misintrerpreting the zlevel purpose.

[helgasoft]

Thank you for the good example. Appears to be a disturbing behavior in setOption.
The overlap is not an issue here. One could create layers with 'z' or 'zlevel' or just by adding the uppermost series last.
But setOption redrawing unchanged series is a serious flaw to me - Demo.
Documentation for Normal Merge says:
"No existing component will be removed. Only add and update are supported in this mode."
Redraw isn't mentioned, but am I the only one who believes it's implied?