Grouped views do not allow for vertical scrolling & Group Expansion Outside Initial Viewport

[zpp-andy]

Regarding ticket #4219, here is another attempt to report this bug to find a (better) solution. Unfortunately, there is no solution to this problem since 06.2023. Setting the renderVerticalBuffer to a high pixel value is only a conditional solution and will greatly affect the display speed for large tables.

Describe the bug

Issue 1: Vertical Scrolling in Grouped Views
In version 5.5.0, grouped views do not allow for vertical scrolling without manually setting a large renderVerticalBuffer.
It appears that the automatic calculation of the buffer is not functioning correctly for grouped views.

Issue 2: Group Expansion Outside Initial Viewport
When expanding groupings that are outside the initial visible section of the window, the grouping expands but the view jumps to the beginning of the table instead of keeping the expanded section in the visible area.

I expect the same behaviour as up to version 5.4.4. I think that a change/optimisation of the render is responsible for the behaviour. (https://tabulator.info/docs/5.5/release#performance)

Tabulator Info
Tabulator affected Version: >= 5.5.0
Previous Version (without issues): 5.4.4

Both problems are specific to version 5.5.0 and higher
These problems are also present in the latest version 6.2.1

Working Example
https://jsfiddle.net/syh7kjrm/9/

The problems do not occur in version 5.4.4.
https://jsfiddle.net/5o09y8nd/20/

To Reproduce
Issue 1:

1. scroll down

Issue 2:

1. scroll past the first screen
2. click on a category to open it

Expected behavior
Issue 1:
I expect to be able to scroll to the end without any problems.

Issue 2:
I expect that when opening a category, the system does not jump to another area.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop:

• OS: Windows 10
• Browser chrome
• Version 125

Additional context
Possible solution
One possible solution is to set the "renderVerticalBuffer (https://tabulator.info/docs/6.2/layout#virtual-dom-buffer)".
But I think this is just a workarount and does not fix the error.