All Calendars is a feature that generates an overall view for all of your project's default calendars. Rather than viewing each calendar separately, view them all at once by following these steps.
Step 1 — Access All Calendars
From the Projects page, click the All Calendars Icon in the sidebar.
Step 2 — Hide Calendars
The Right Arrow Icon (▶︎) means a calendar is from hidden view. Click the icon to view the projects calendar.
Step 3 — View Calendars
The Down Arrow Icon (▼) means a calendar is enabled to view. Click the icon to hide a projects calendar.