Microsoft is rolling out Windows 10 20H1 Build 18950 to Windows Insiders in the Fast ring. This build includes improvements to the Japanese IME and Snip & Sketch improvements. Microsoft will promote the WIN+Shift+S keyboard combination to create a new snip from within the Snip and Sketch canvas space. This includes a single window mode that will open new snips in the same window rather than opening up a ton of Snip windows. This feature is not working yet and will be available to test at a later date.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-insider-build-18950-released-with-snip-and-sketch-improvements/