Windows Vista build 5212 (winmain)

Windows Vista build 5212 (winmain) is a pre-Beta 2 build of Windows Vista. This build was leaked on 2016-12-19 to BetaArchive. Aero can be enabled on this build in VMware, unlike 5112, but it looks identical to the aforementioned build.

This is the leaked winmain compile, and it's not to be confused with the vbl_ux_dev_checkin compile.

Setup
Although setup is similar to aforementioned builds of Vista, the autorun prompt upon booting into setup now fits more perfectly on the screen and is positioned correctly. Fonts used in the first page of setup also now use anti-aliasing once again.

Changes and new features

 * The watermark now states Beta 2 rather than Beta 1.
 * The Avalon/Indigo and fundamental drivers shortcuts have now been removed.
 * Upon right clicking on applications, a new "Run Elevated..." prompt will appear. This essentially runs applications under administrative privileges.

New apps

 * Windows Media Center is included in this build, and it features a drastically different look compared to the one featured in Windows XP Media Center Edition 2005. It is also included on the taskbar by default.
 * Windows Calendar has been added.

Flip3D
This is the first leaked build to introduce what was known as Flip3D. It contains similar functionality to ALT+TAB, however it now utilizes the Desktop Window Manager in this build and creates a 3D flipping effect in between all of the applications currently open, thus the name "Flip3D". Flip3D can be used via pressing WIN+SPACE, rather than WIN+TAB which was used in later builds.

Sidebar
Just like Flip3D, this is also the first leaked build to reintroduce the Sidebar. This was included in the very first leaked build of Longhorn, however it was relatively unstable and oftenly caused memory leaks - especially in later builds. To help prevent any memory leaks and such with the reintroduction of the Sidebar in this build, the Sidebar now has its own process (called sidebar.exe), rather than being integrated into Windows Explorer. This process, however, isn't shown upon boot, and the user must run said process from the start menu.

Bugs

 * If launching the Sidebar process and then terminating it, the watermark may not position itself correctly.
 * Apps shown on the taskbar may appear at the very end of the taskbar.
 * If recycling something or adding something to the recycle bin, the icons won't change unless you log out and log back in.