Unplanned
Last Updated: 28 Feb 2025 10:53 by ADMIN
Serhii
Created on: 14 Feb 2025 00:28
Category: Gantt
Type: Bug Report
0
[Gantt] Items on the timeline are misspossitioned when one item spans over daylight saving time

It seems that whenever a task crosses the date where the daylight saving time switch appears everything on the gantt's week view gets shifted by 1 hour.

This stackblitz shows 2 Gantts. The first one has correct positioning, the second one appears to be bugged.

In this picture, you can see that in the 1st Gantt `Item 1` is slightly shifted to the right and covers Thursday and Friday. That's because its date is specified in UTC as `2025-04-03T00:00:00.000Z` which, for me in the UK, will result in `01:00:00.000`.
However, in the second Gantt `Item 1` now fully covers Thursday and doesn't extend to Friday even though the start and end dates are the same as in the first Gantt.

You might get slightly different positioning based on your time zone. The description is written based on the UK time zone.

It also affects drag-and-drop marquee. If you try to drag the right side of item 1, you'll see that it will show Saturday even before it starts covering Saturday.

Expected behaviour: Item 1 has to be positioned identically on both timelines

3 comments
ADMIN
Georgi
Posted on: 28 Feb 2025 10:53

Hi Serhii,

Thank you very much for the clarifications provided.

Thanks to the runnable StackBlitz demo and the YouTube video that were provided in the thread, I indeed managed to reproduce the unexpected positioning of the tasks inside the Kendo UI for Angular Gantt, when there is a task displayed in the component that spans daylight saving.

Having further investigated the matter, it turned out that the current behavior of the Gantt component is indeed a bug on our side. For this reason, I logged an issue in our public GitHub repository, and what I would suggest would be to subscribe to it in order to track the resolution process:

It is also worth noting that subscribing to this item in the Feedback Portal would also allow you to receive updates about any status changes.

As a token of gratitude for pointing out this issue to us, I updated your Telerik Points.

In these lines of words, I would like to apologize for any inconvenience that this unexpected behavior might be causing.

Please, let me know if I can further assist you with this case.

Regards,
Georgi
Progress Telerik

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Serhii
Posted on: 24 Feb 2025 01:49

Hi Georgi.

Sorry, I uploaded the wrong stackblitz. This one should show two gantts.

https://stackblitz.com/edit/angular-ussdl9ho-mbkchtyb?file=src%2Fapp%2Fapp.component.ts

I also attached a video link showcasing the issue (I couldn't upload the file). This representation and dates are valid for the London time zone. If you are in a country that switches to DST on a different date or time you'll have to adjust them.

https://www.youtube.com/watch?v=gBIQjnMRUgc

As you can see in the video item1 is positioned differently in the first and second Gantt despite being the same object for data binding.

ADMIN
Georgi
Posted on: 20 Feb 2025 11:07

Hi Serhii,

Thank you very much for the screenshots provided.

I tried opening the StackBlitz demo that was attached to the thread, but it seems like there might be some issue with the demo link as it visualizes just a single Kendo UI for Angular Gantt component. For reference, here is how the StackBlitz demo loads on my side when forked:

Be that as it may, I tried reproducing the issue with the daylight time shift in the provided Gantt configuration. However, it seems like I am missing out on some of the reproduction steps since the tasks are correctly rendered on my side in accordance with the timezone of the machine:

Since I want to avoid misunderstandings and provide the maximum utility out of the support service, I would ask you to provide more detailed information about the specifics of the configuration of the second Gantt component or, ideally, the demo with the two Gantt components and some more detailed reproduction steps. This would allow me to replicate the discrepancy on my side, debug it, and thus come up with a more suitable suggestion.

I am looking forward to your reply. 

Regards,
Georgi
Progress Telerik

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