Microsoft 365 Developer Day

Recently, at Microsoft 365 developer day, the company showed its vision for dual screens.

Recently, Microsoft showed its vision for dual screens and shared how dual-screen devices are optimized for the way people naturally work and want to get things done.
The company shared how the apps work and how people can optimize for three dual-screen patterns whether they are building apps for Windows, Android, or the Web; which are - Expansive workspaces, Focused screens and Connected apps.
You can show more detail as your app spans across two screens and allows you to highlight your content on a bigger, more expansive, canvas. Dual-screen devices allow you to see your app on one screen and your tools on the other and stay in your flow.
Microsoft said that the company is maintaining app compatibility and ensuring your existing websites and apps work well on dual-screen devices.
"Windows 10X is an expression of Windows 10 and for the first-time apps will run in containers to deliver non-intrusive updates and improved system resources for extended battery life." wrote Microsoft.
The company also announced that you can now download and install the Microsoft Emulator and tools to start developing apps and testing your apps for Windows 10X. Moreover, the company has also updated the preview SDK for Surface Duo in order to include all Java native samples as Kotlin samples, drag-and-drop to help you capture the value of moving data between two apps on dual-screen devices. The update will also support users on MacOS, Linux (Ubuntu), and Windows with Android Studio, Visual Studio, and VS code integration.
You can watch the event highlights here. 
Microsoft has also proposed a new JavaScript API and a CSS media query with a set of pre-defined env() variables. The company is working with the Second-screen and CSS Working Groups at the W3C, and as the standards process progresses, Microsoft intends to contribute its implementation to Chromium.
The company has also introduced new features in the Microsoft Edge DevTools which enables you to simulate and remotely debug dual-screen devices from Microsoft Edge on your desktop.
Well, in order to help people utilize all the possibilities for dual-screen devices the company has built the TwoPaneView control, which automatically optimizes and adjusts one's app so that one can focus on his content and see how the app will respond when spanned or rotated.
You can utilize the new dual-screen SDK for Xamarin.Forms in order to build apps across Windows 10X and Android. This SDK packs a new TwoPaneView control and APIs such as the DualScreenInfo helper class to help access important information and build beautiful dual-screen apps.
Source: Microsoft 
You can also download the early sneak preview of the React Native dual-screen modules, which is a TwoPaneView component analogous to WinUI and Xamarin.Forms controls, and a lower-level DualScreenInfo module that returns usable screen regions around the seam and spanning events.