As you may remember, Microsoft is testing an update to Cortana in Windows 10. In the latest Insider Preview build, developers separated Cortana and search in the taskbar by giving them individual taskbar buttons and flyouts. A server-side change adds a new section to the search pane.
As you may remember, Microsoft has introduced Fluent Design with Windows 10.
Fluent Design is the modern Windows 10 UI, previously known by its code name "Project NEON". It is a new design language which is focused on simplicity and consistency along with cool animations. It also adds Windows 7’s Aero Glass-like effects to the Universal app frame and controls.
Key aspects of the Microsoft Fluent Design System are as follows.
Material: A graphical solution which emulates the "sensory and invigorating" feel of the materials that things around us are made of.
Motion: A set of animations which give an idea on how to interact with new UI elements like an app menu opening or drawing the user's attention to controls and flyouts which appear on the screen.
Light: Soft highlights of important buttons and features to draw the user's attention.
Depth: Transition animations which make an impression of opening the next level or layer of data presented by the app.
Fluent Design inherited flat icons and square corners from its predecessor, 'Metro', the design language of Windows 8. Finally, Microsoft decided to update the style of the apps.
In the development branch of Windows 10 that represents the upcoming version 20H1 of the OS, the search pane comes with rounded corners. According to Zac Bowden, these rounded corners are coming to Fluent Design. You'll see it all over Windows, Xbox, Office, and other products in the coming months/years. The rounded tabs in Microsoft Edge Chromium are another confirmation for the upcoming changes in design.
Source: Zac Bowden.