A new feature which rolled out with the Redstone 5 Insider Preview is Sets. This particular feature has been boosting my productivity.
Sets allows to have tabs (similar to the tabs that we get in web browsers) in all applications including Windows Explorer, Microsoft Word, Microsoft Excel, etc. This allows us to work with multiple files within the same Window than opening multiple instances of the same program. Navigation is super easy with this.
For an example, when I open my Outlook, my inbox is displayed in one tab and the emails I open are shown in individual separate tabs.
Furthermore, it helps us to to have tabs from different applications as well. the following screenshot shows the first two tabs are Microsoft Word files and then an Excel file followed by the Windows explorer.
As of today, clicking of the + sign on the main title bar enables you to open a Microsoft Edge browser but with the final version of Redstone 5, I think we will have a list of applications that can be opened or application specific tabs could be open.