https://mspoweruser.com/windows-10-build-14942-released-to-windows-insiders/

"In addition to this, Microsoft is adding the ability to hide the app list in Start Menu — a much-requested feature."

https://blogs.windows.com/windowsexperience/2016/10/07/announcing-windows-10-insider-preview-build-14942-for-pc/#LsXyK6OCFwIWqemG.97

Hide app list on Start:

We are releasing a new feature that enables you to collapse the app list in the Start menu. This has been a top feedback request from Windows Insiders. You can try it out by going to Settings > Personalization > Start and turning on “Hide app list in Start menu”.