Processing Speed When Moving Tasks in the Gantt Chart Component

[Ryo Moekui]

I would like to ask for suggestions on how to improve the Gantt chart component.

In a Gantt chart with multiple tasks, when I perform task reordering operations (for example, swapping the order of TaskID29 and TaskID32 in the sample below using drag-and-drop) multiple times (20 or more times), I notice that the processing speed seems to gradually slow down.

https://stackblitz.com/edit/react-jhyzwjqs-31ja5qur

Additionally, in a similar Gantt chart, if I swap tasks (about 10 times), leave it idle for a certain period (about 10–20 seconds), and then swap tasks again, I notice that the processing speed seems to slow down.

Since I’d like to be able to perform multiple task swaps smoothly, I’d appreciate any solutions to prevent this slowdown.

Also, although this is different from moving tasks, I observed a similar slowdown in processing speed when repeatedly clicking the expand/collapse button on a parent task,

so I’m sharing this information in case it’s helpful.

I would appreciate your guidance on this matter.

[Ajithkumar Gopalakrishnan]

Hi Ryo Moekui,

Greetings from Syncfusion Support,

Based on your query, we understand that when performing row drag-and-drop repeatedly (more than 20 times), the task positions change frequently, and parent records expand and collapse rapidly. This results in slower performance in the Gantt Chart.

We have validated the shared details and tested the attached sample on our end. We observed that when row drag-and-drop and expand/collapse actions are performed rapidly (more than 20 times), the actions take longer to complete in the Gantt Chart.

Please refer to the attached video for reference. Two scenarios are included in the video. Kindly confirm whether the same behavior is observed on your end.

Once confirmed, we will proceed with further analysis and provide an appropriate solution. If you are experiencing a different issue, please share a video from your end for further validation.

Regards,
Ajithkumar G

Attachment: expand_(2)_5859bbc.zip

[Ryo Moekui]

Thank you for your reply.

I reviewed the video you provided. I confirmed that the same issue occurs here as well.

I would appreciate it if you could provide a solution that prevents this issue from occurring.

Thank you in advance.

[Ajithkumar Gopalakrishnan]

Hi Ryo Moekui,

We appreciate your patience.

Based on your query, we understand that when multiple column templates are used, actions such as expand/collapse and row drag-and-drop initially perform as expected. However, after repeating the same actions multiple times (more than 20 times), the actions take longer to complete, resulting in noticeable performance degradation. We have logged the reported issue, “Performance degradation after repeated actions with column templates” as a bug. Our team is actively working on a fix, and we plan to include it in the July 14, 2026 patch release.

You can track the progress of the resolution by visiting the feedback link provided below:

Feedback link: https://www.syncfusion.com/feedback/74713/performance-degradation-after-repeated-actions-with-column-templates

Disclaimer: Inclusion of this solution in the patch release may change due to other factors including but not limited to QA checks and works reprioritization.

Regards,
Ajithkumar G

[Ajithkumar Gopalakrishnan]

Hi Ryo Moekui,

Sorry for the inconvenience caused.

As we need to ensure proper coverage of all related use cases, we were unable to include the fix for the issue, “Performance degradation after repeated actions with column templates” in the patch release scheduled for July 14, 2026. we plan to include it in the July 21, 2026, patch release.

We sincerely apologize for any inconvenience this may cause and appreciate your understanding and patience.

Regards,
Ajithkumar G

[Ajithkumar Gopalakrishnan]

Hi Ryo Moekui,

We appreciate your patience.

We are glad to announce that we have included the fix for the issue “Performance degradation after repeated interactions with column templates” in our 34.1.32 release. So please upgrade to our latest version of the Syncfusion package to resolve the reported issue.

Root Cause: When using column templates in the React sample, performing collapse/expand operations or row drag-and-drop does not trigger a grid refresh. This causes performance and rendering issues.

Solution: Added logic to refresh the grid during collapse/expand operations and row drag-and-drop actions. Restricted the grid refresh behavior to scenarios where enableMultiTaskbar is set to true.

Sample link: https://stackblitz.com/edit/react-jhyzwjqs-lpcnwkqs?file=package.json

Release notes: https://ej2.syncfusion.com/react/documentation/release-notes/34.1.30?type=all#ganttchart

We thank you for your support and appreciate your patience in waiting for this release. Please get back to us if you need any further assistance.

Regards,
Ajithkumar G