Here, you define what data will be included into a chart.

We strongly recommend you to use the scheduling mode by task start as scheduling by task end may significantly slow down a chart generation.

If scheduling mode is set by task end, planning by whole days is strongly recommended. Planning in hours and minutes may lead to incorrect app behavior.

Please note that the tasks will acquire a fixed duration, once edited on a chart that is configured with a task duration calculation Calculated based on start and end dates only. Meaning that duration will be changed without affecting the task estimates in Jira. Thus, you may want to rely on this information when editing tasks via drag-and-drop or resizing.

Even though the task duration is switched to Calculated based on provided estimate, otherwise based on start and end dates, the described above behavior will be observed. In order to reset the behavior you would have to clear task duration on Edit dialog.

To summarize, this option allows everybody to see a chart like the impersonation person does (even though, viewers might not have have the required Jira permissions).