Follow these steps:
In the left-side navigation panel, click the name of the email folder that you want to read.
To open a specific message, click the corresponding mail row.
Double-click the subject to open the message in a new tab.
The Inbox tab remains open. If you open several messages, they display as separate tabs.
Alternatively, press the Enter key to open the message in a new tab.
When you finish reading the message, close the tab to return to the message list of the current folder.