Windows "desks"

I've been away from this for a long time, so I may have missed the memo.  But during the preview versions of 10 I seem to remember that users were able to create multiple "desks," one for each project they were working on, with different opened applications and files.  The icon for the desks was what is now the "Task View" next to the search window at the left of the taskbar.

I thought that was a great idea!  When did that go away?  Or am I dreaming?