ListBox virtualization with variable item height and random scroll behavior

[agnauck]

Describe the bug
A ListBox that has items of different height and virtualization scrolling does not work always correctly.
By scrolling up and down the whole list using the scrollbar the last items is always positioned different on each run.

• Sometimes there is remaining free space, the free space at the end that varies on each run
• Sometimes the last item cannot be scrolled into the view completely, its only partly visible

To Reproduce
This can be reproduced with the VirtualizationDemo when randomizing the item size and then scrolling up and down multiple times using the scrollbar.

Expected behavior
I would expect that the last item is always positioned exactly the same.
I would expect that the last item is visible always completely when scrolling to the end of the list

Screenshots

Desktop (please complete the following information):

• Windows 11
• Version: latest nightly (0.10.999-cibuild0021189-beta)

Additional context

• This is also effect scrolling to specific items from code
• It also effect monitoring the scroll position from code, like detecting a scrolled to end event