Critical Path not correct with the lead time.

[Abdul Waheed]

I have used the official react js demo of critical path. I have lead time of two days in the schedule. The default behavior if it has lead time means there will the slack value the the task is not critical. And the slack are also not calcu

Attachment: Screenshot_20251222_at_22.04.55_a5a2b03.png

[Ajithkumar Gopalakrishnan]

Hi Abdul,

We have reviewed your query, and we are able to replicate the issue "Critical path tasks are not calculated properly " in Gantt Chart. To address the problem, we have logged a bug request, and the fix will be provided in the patch release which is scheduled to be rolled out on January 6, 2026. You can track its status from the feedback link given below.

 
Feedback Link - https://www.syncfusion.com/feedback/71959/critical-path-tasks-are-not-calculated-properly

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 Abdul,

Sorry for the inconvenience caused.

We have resolved the reported critical-path scenario; however, we are still validating additional use cases to ensure full alignment with MS Project behavior. Due to this, the fix could not be included in the January 6, 2026, patch. It is now planned for inclusion in the next patch release on January 13, 2026.

 Until then, we appreciate your patience.

Regards,
Ajithkumar G

[Ajithkumar Gopalakrishnan]

Hi Abdul,

We are glad to announce that we have included the fix for the issue “Critical path tasks are not calculated properly” in our 32.1.23 release. So please upgrade to our latest version of the Syncfusion package to resolve the reported issue.

Root Cause: Slack calculation was calculated wrong which leads to incorrect critical task in updateOffsetOnTaskbarEdit set to false.

Solution: We would like to clarify the behavior of the Gantt chart. In earlier versions, if two tasks were connected with an offset, both tasks were rendered as critical, which caused the reported issue. This has now been fixed based on Microsoft Project behavior:

• On initial load, if there is an offset between two tasks, both tasks are considered critical.
• Example: Task 29 is connected to Task 30 with a predecessor 29FS+2 days. If Task 29 is moved to the right, Task 30’s date changes, so the two-day gap makes the task critical.
• However, if Task 29 is moved to the left (less than the offset), the task is no longer critical. This behavior now matches MS Project and works when updateOffsetOnTaskbarEdit is set to false.

Sample: https://stackblitz.com/edit/react-3r8ipz6e-y8xpfj5m?file=index.js,package.json

Feedback: https://www.syncfusion.com/feedback/71959/critical-path-tasks-are-not-calculated-properly

Release notes: https://ej2.syncfusion.com/documentation/release-notes/32.1.23?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