[grid] When I am on last item before blank space and I scroll, last item flickers

[shekerev-progress]

Bug Report

Current behavior

• We have a grid with virtualization and without rowHeight
• Alternatively: We have a grid with virtualization and rowHeight and grouping
• In both cases we do not know the full height of all rows, so we have some blank space at the end of the grid
• I scroll to the bottom of the grid, to last item, I release keyboard or mouse
• issue 1 - Always - I try to scroll further down, the last item flickers
• issue 2 - Sometimes, randomly - I try to scroll further down with keyboard or mouse, the last item disappears and I have no items on page
• issue 3 - Sometimes, randomly - I try to scroll up, my position is reset and after scroll I still see only the last item
• I managed to reproduce all 3 with both mouse and keyboard

Expected behavior:

• All 3 should not happen

Example demo: https://www.telerik.com/kendo-react-ui/components/grid/grouping/grouping-virtual/

Environment:

• Win 10, reproduced with IE, Chrome, Firefox

[simonssspirit]

Reported again in ticket: 1402906 Please check with priority.

[skyfx64]

Hello team.. any update ?.

Thanks'

[Xizario]

@skyfx64, it is not fixed, I will keep you updated. Probably will take this next week.

[skyfx64]

Hi @Xizario : any update ?.

Thanks'

[simonssspirit]

Reported again in: 1426050

[simonssspirit]

Reported again in 1430942

[skonakanchi1]

Any Update on this bug?

[simonssspirit]

This is currently worked on.

The idea is that we will rework the entire way the virtualization is done. This is why this task is quite a big one and it takes more time.

We will post updates as soon as we have something in dev channel.

[meyerds]

@simonssspirit any updates on the virtualization rework?

[simonssspirit]

The team is still working on it. We made changes, but as we have to remove the componentWillReceive props(deprecated by React), this will cause breaking changes. This is why we are still holding on the changes.

[meyerds]

@simonssspirit do you have a release planned, or is this far future?

[simonssspirit]

A specific date is hard to say, as it is proven to be more complex than anticipated. The team is working on it, so we hope that it won`t be so far in the future.

[alpavlove]

Any updates with this?

[Xizario]

Additional details here: https://www.telerik.com/forums/grid-grouping-with-virtual-scrolling-issues

We have still not found solution, the only possible way for now seems to be requiring all the data to be available for the calculations, and this is something we want avoid.

Update to the original post: We suggest you to use the TreeList (was not available back then, but it is now) for when you want to show hierarchical structure, it supports virtualization as well, and behaves more predictable than the grouping, yet it can show exactly the same data if structured correctly, Also will be able to expand and collapse with the virtualization, something not possible with the grid.

[simonssspirit]

To everyone:

We have a suggestion on how this could be resolved. The suggestion has its limitations as after long research (including years of experience making data Grids for different technologies ) we know that both approaches have limitations and the developer has to choose which one is better based on the real application use case.

If you like the idea please visit the GitHub item, vote for it, and comment, your opinion is very valuable to us:

https://github.com/telerik/kendo-react/issues/795