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Last Updated: 30 Oct 2025 08:26 by ADMIN
Andrei
Created on: 09 Oct 2025 11:46
Category: KendoReact
Type: Bug Report
0
Error when resizing the container in the treelist
We use "@progress/kendo-react-treelist": "^5.10.1" in our project. Trees are usually placed in flexible containers, and users can reduce their size to 0. At this point, we get an error when calling the tableRowsVirtualization function. I have attached a screenshot at the moment of debugging. You can see that the values of items[0] and lastItem are undefined when the container size approaches 0. I didn't prepare an example to reproduce the error, because I think it's pretty clear that an error occurs here. So the questions are: if this is a bug, is it fixed in the new versions of the package? If there is a possible error on our part or it has not been fixed in the new versions, then what should we do to solve the problem? Thanks
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5 comments
ADMIN
Filip
Posted on: 30 Oct 2025 08:25

Hi, Andrei,

Thank you for the sent project. I ran it locally and debugged it after I reduced the container height to zero, however the item was not undefined as seen in the screenshot. I have attached the result from the debugging here:

Can you please confirm if I’m following the correct steps (specifically, resizing the container to zero)? I reviewed our closed issues to check whether this might have been a bug in an older version that was later fixed, but I couldn’t find any responses. I suggest upgrading to the latest version (12.2.0), as many improvements have been made, and the issue may already be resolved in recent releases.

Regards,
Filip
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Andrei
Posted on: 23 Oct 2025 08:59
Hi, Fillip! thanks for the prepared example. the attachment contains an archive of the project with the possibility of reproducing the error. the problem began to recur after adding virtual scrolling. to do this, I set the scrollable="virtual" and height properties in the style property according to how it is described on the website in the section on virtual scrolling for the TreeList component. I also attached a screenshot again where you can see that lastItem takes the undefined value, which subsequently causes an error. thanks
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ADMIN
Filip
Posted on: 22 Oct 2025 18:33

Hi, Andrei,

It seems that I have attached the wrong project, please accept my apologies for the oversight. I have attached the react project that I tested in which the TreeList is placed inside a flexible container, I have attached it to this ticket. If possible can you please configure it so that it matches your scenario and the issue reproduces? 

Please accept my apologies for the oversight earlier once again.

Regards,
Filip
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Andrei
Posted on: 17 Oct 2025 13:50
I just want to clarify if I was understood correctly. we are using "@progress/kendo-react-treelist": "^5.10.1". the package for React, but I received an example for Vue in the attachment. just in case, I want to clarify whether you have tested the React package?
ADMIN
Filip
Posted on: 16 Oct 2025 08:34

Hi, Andrei,

Thank you for the provided screenshot. I went through our public issues and tickets in order to see if someone else had reported the same error, however it seems that this is the first report so far. I tested the TreeList component with both version 5.10.1 and the latest one (12.0.2) in order to reproduce it, however I was not able to. 

I agree that there is an issue based on the screenshot, however we will need to reproduce it locally in order to determine if it's a bug on our end or due to the configuration. I have attached the test project to this ticket. If possible can you please modify it so that the issue reproduces? This will enable me to investigate further if this is a bug and if upgrading to a newer version would resolve it.

Regards,
Filip
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