Microsoft is rolling out a new Notebook UI for Cortana in the latest Windows 10 Insider Preview builds.
Microsoft is building a brand new Cortana Notebook user-interface for the upcoming version of Windows 10, codenamed Redstone 4. Spotted on Reddit (via Thurrott,) the new UI is currently in testing with Insiders in the Fast ring, and can be found in the Cortana Notebook area within the Cortana search UI.
Full story from the WindowsCentral blog...