Build 3706 was leaked on 22nd May 2006 as an x86 Professional compile. It is one of only a few builds that are confirmed to contain a working start page. The Desktop Composition Engine (DCE) is partially implemented in this build.
This build is the first to include the new taskbar. However, the taskbar is not a separate panel in this build yet, and therefore when enabled, shows the taskbar acting like a tile on the sidebar. Also included in this build is the all new My TV and Movies library.