Vtiger Calendar is a Vtiger extension which is designed to display all the users/group as rows, and the hours, days, weeks as columns.with this extension user can see events assigned to other users without overlapping them. Comparing with the standard calendar Vtiger calendar has many features as users can edit an event, create new within just one click and also display tasks, events, invoices, birthdays, etc. Also, the user can assign text in the tile/box and also configure colors based on the status.