In 2017, Microsoft officials provided a preview of two new features coming to Windows 10: Timeline and Sets. Timeline made it into Windows 10 as part of the April 2018 Update, but Sets didn't. And it's looking like it never will be included in Windows 10.
My sources say Microsoft dropped plans for Sets, a Windows-management feature, which would have allowed users to group app data, websites and other information in tabs, months ago. Although Microsoft did test Sets last year with some of its Windows Insider testers, the feature generally wasn't well received or understood. For apps like Office to work well with Sets, the Office engineering team was going to have to do a lot of extra work.
Sets didn't make an reappearance in the Insider test builds leading up to the May 2019 Update/1903, and officials haven't mentioned the Sets feature in months.
Over the weekend, Microsoft Senior Program Manager Rich Turner tweeted "The Shell-provided tab experience is no more, but adding tabs is high on our to do list." (That's likely the closest we will get to an "official" comment on the future of the Sets feature.)
Turner pointed to a Devblogs.Microsoft.com post originally dated June 29 about tabs coming to the Windows Console. At that point in time, the Console team was planning to use the new Sets feature as the base for adding Tabs in the Windows Console. But since the Windows team has decided against moving forward with Sets, the Console team is now going to have to build Tabs into the Console without using Sets as the foundation, my sources say.
When Microsoft first unveiled Sets, officials said the feature might or might not make it into the Windows 10 April 2018 Update. But the goal was to ship that feature at some point as part of a Windows 10 feature update.
At first, Sets was going to work only with Universal Windows Platform (UWP) applications. But over time, Microsoft was planning to optimize full Win32 apps like Office to work with the Sets tabs. Microsoft officials also were hoping to help third-party Win32 apps to be optimized to work with Sets over time.
When the Microsoft Edge team began work on moving to the Chromium engine last year, they had to make a choice about whether or not to redo the work necessary to integrate with Sets. Doing so could have delayed Chromium-based Edge significantly -- or resulted in Sets integration not coming to the new Edge browser until months after it debuted. So that helped finalize the decision to table Sets, my contacts say.
Windows users who still want a feature like Sets can buy the Stardock application called "Groupy," which allows users to group app data, websites and other information in tabs.