This setting affects the taskbar buttons used to switch between running programs.Taskbar grouping consolidates similar applications when there is no room on the taskbar. It kicks in when the user's taskbar is full.If you enable this setting it prevents the taskbar from grouping items that share the same program name. By default this setting is always enabled.If you disable or do not configure it items on the taskbar that share the same program are grouped together. The users have the option to disable grouping if they choose.
Start Menu and Taskbar
At least Windows Server 2003 operating systems or Windows XP Professional