In the new version 4.0v, you can open and preview multiple documents at the same time. This functionality was not there in the legacy version 3x.
New Version 4.0
To open multiple documents, select all the documents that you want to open. Let's say you select 3 documents, then go to the 'Actions' button on the top right and click on 'Open 3 Documents'. A new window with 3 tabs will open. Each tab will have the preview for each document as shown below.
Legacy Version 3x
In the legacy version, one could open only one document at a time.
