In order to see E-Mail folders shared by other users, you have to subscribe to those folders.
How to subscribe to shared E-Mail folders:
Click theicon on the right side of the menu bar. Click the menu item.
Click onin the sidebar.
Click onin the display area.
In the Subscribe IMAP folders window activate the checkboxes of the folders that you want to subscribe to. Click on .
Parent topic: Sharing Data