Work Time Calendar for Jira can be launched from a project context. The calendar that is launched in a project context view shows the events that are based on the sources that are configured as "All projects" sources and the sources that are configured specifically for the current project.
To open Work Time Calendar in a project context view, click the Work Time Calendar icon, on the left menu.
Your can create new calendars or edit existing ones without leaving the project context. The main buttons are accessible, assuming you have the required permissions.