Interactive playgrounds return in Xcode 7.3 Beta 2. These were a thing that got put aside when Apple integrated the iOS simulator into the playground assistant, and have finally re-emerged. Here’s an example in action. The following demonstration creates a view controller instance and ties a switch to a custom action callback.
Unfortunately, a lot of the tricks I used to do to create full-class OS X apps that supported drag and drop into playground windows are no longer working under the current system. I could, however, create a basic interactive NSView that properly handled mouse events:
I’m a little sad about the wider drag-and-drop utility for system interaction being lost. I’m hoping this returns in a later beta.