Windows Longhorn build 4020

Windows Longhorn build 4020 is a Milestone 5 build of Windows Longhorn. A screenshot of the build was leaked on the BetaArchive Discord on 2018-11-27. Longhorn.at.ua also has a few images of this build. On 2018-12-03, this build was leaked to the BetaArchive FTP by ReflectiaX, along with 4032.

New features and changes
This build is very similar to build 4015 (main), however there are some minor changes:
 * Notably, the notifications appearance has been updated, and now uses the new design from build 4029, which features a more sleeker design and the notification icon on the side bouncing up and down when hovered.
 * The Windows Explorer has been updated to no longer leak memory when the Windows Sidebar is enabled. WinFS also works in this build, just like in 4015.
 * The OOBE is now completely skipped; after the hardware portion of setup, the system logs on to the Administrator account.
 * This build changes the "Longhorn XP" references to simply "Longhorn", such as in the desktop watermark.
 * The sidebar is given a minor change to take up the whole side, including the bottom of the taskbar, shifting the time to the left of the sidebar instead of under.

Hidden dialogs
There are a few dialogs that cannot be accessed normally. They are:
 * Security preferences - Allows you to set preferences for security. It does not seem to have any effect.
 * Installer warning dialog

Hidden sidebar tiles
There are a few sidebar tiles that are disabled by default in this build. They are:
 * RMA Test Tile - In this build, it only shows the title of the tile, and nothing else is there.
 * Longhorn Status - By default links to
 * Messenger Status Tile - This tile only works if you are using Windows Messenger. You cannot use MSN Messenger with this tile. Also, this tile does not work with Windows Messenger 4.0, you will need 4.6 or 4.7 for it to function correctly.

Bugs

 * The Desktop Composition Engine is broken in this build, so window transparency cannot be enabled.

Installation
The installation media is not bootable, you must upgrade to this build from an earlier version of Windows.

Desktop
If you uncheck "Show Desktop Icons", you will not be able to right click or drag select on the desktop.