<P> Windows Aero (a backronym for Authentic, Energetic, Reflective, and Open, or simply AERO or Aero), also known as Aero Glass, is a design language introduced by the Windows Vista operating system . The changes made in the Aero interface affected many elements of the Windows interface, including the incorporation of a new look, along with changes in interface guidelines reflecting appearance, layout, and the phrasing and tone of instructions and other text in applications . </P> <P> Windows Aero was in force during the development of Windows Vista and Windows 7 . In 2012, with the development of Windows Server 2012 (and later, Windows 8), Microsoft moved on to a design language codenamed "Metro". </P>

Which of the following is not windows 7 aero feature