Unable to scroll Virtualised Blazor DropDownList/Multiselect above selected item

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Duplicated

Last Updated: 24 Jul 2023 07:27 by Mark

Mark

Created on: 10 Jul 2023 12:58

Category: UI for Blazor

Type: Bug Report

Unable to scroll Virtualised Blazor DropDownList/Multiselect above selected item

Unexpected scroll behaviour is seen after selecting an item in a DropDownList/Multiselect with a scroll mode set to virtualise. We are unable to easily scroll upwards using the scroll bar in the control or using a mouse/trackpad. The scroll position immediately snaps back to the selected item. Sometimes we are able 'escape' this by rapidly scrolling but this does not feel like intended behaviour.

Downward scrolling seems okay and using the keyboard arrow keys also seems unaffected. This is reproducible on the demo page: Blazor DropDownList - Virtualization - Telerik UI for Blazor and https://docs.telerik.com/blazor-ui/components/multiselect/virtualization.

Reproduction steps on Chrome:

Navigate to demo page and render local example preview
Select item "Name 27"
try to scroll up with the arrow buttons on the scrollbar or the mouse wheel

Minimal reproducible example: Blazor MultiSelect - Virtualization - Telerik UI for Blazor

Attached Files:

multiselect-unable-to-scroll.gif

Duplicated

This item is a duplicate of an already existing item. You can find the original item here:

ComboBox virtual scrolling breaks when you slowly scroll up after selecting an item. The same behavior goes with the virtualization in DropDownList.

5 comments

Mark

Posted on: 24 Jul 2023 07:27

Thank you for both for your comments. May I just add to Constantinos response in saying that using a mouse wheel and trackpad was also specified in the main description. Dimo, It is confusing to then only respond specifically to the scroll bar usage.

Nonetheless, this is captured in Constantinos bug request and I too hope for a resolution in the near future.

Constantinos Petridis

Posted on: 21 Jul 2023 08:40

Hi Dimo, as the original bug report states, wheel scroll also has the same problem. The issue has not "survived" for so long because you can use the mouse wheel or track pad, and hence one would say that it is not noticeable...

If you want my opinion, on why it "survived" for so long (which I cannot prove) is that, since I have posted the bug report stating that a page size of 10 makes the problem barrable, all virtualization demos and examples have changed from a pagesize of 20 to 10. Most of us (developers using your controls) just copy paste the examples and only change the look and feel... we never notice the bug. And that is why it "survived" for so long...

As Mark stated in my original thread, I am frustrated because I have to defend Telerik's "shortcomings" to my managers when they ask me why our product needs to make so many calls to our API server in order to fetch records for the combo/dropdown or multiselect controls, when a larger page size would solve this issue.

Anyway, I am still optimistic that the bug will not reach its two year anniversary

ADMIN

Dimo

Posted on: 21 Jul 2023 07:05

Hello Mark,

I agree that old bugs may not look good, but it boils down to priority and customer demand. The issue "survived" for so long because most users scroll via the mouse wheel or track pad, rather than clicking on the scrollbar itself.

Nevertheless, I confirm that the bug has gained enough traction and it is in our backlog since recently. As soon as we schedule it for implementation, the item status will change.

Regards,
Dimo
Progress Telerik

Stay tuned by visiting our public roadmap and feedback portal pages! Or perhaps, if you are new to our Telerik family, check out our getting started resources!

Mark

Posted on: 20 Jul 2023 19:40

Thank you for the response. It is very disconcerting to be referred to a bug report from 2 Dec 2021. I don't see how the virtualization of a select list is considered as a feature in this state.

ADMIN

Dimo

Posted on: 17 Jul 2023 07:51

Hi Mark,

I think this is the same issue as this one - Virtual scrolling breaks when you slowly scroll up after selecting an item.

Please accept my apologies for the troubles this UX bug may be causing. I hope users will manage to scroll with the mouse or via swiping.

Regards,
Dimo
Progress Telerik

Stay tuned by visiting our public roadmap and feedback portal pages! Or perhaps, if you are new to our Telerik family, check out our getting started resources!