Note: this property is set by the MenuTool if the gallery is the first visible item in the menu. It is intended for use within the style of the tool to trigger the display of separators.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2