Company Calendar for Jira can be launched from a project context. In this mode, the calendar shows the events that are configured for the current project. The screen looks next:
Please note that, starting version 4.0, a user can create new calendars or edit existing ones without leaving the project context.
Please note that if "All projects" is selected for a source that has been configured, then, the events created based on the source are not associated with any specific project. So, they wouldn't be displayed in a calendar that is opened in project context.