Finalmente, encontrei a resposta no microsoft.com . Eu odeio esse recurso também.
If you don't want to group taskbar buttons, you can turn off grouping. But without grouping, you might not be able to see all of your taskbar buttons at once.
To stop grouping similar taskbar buttons on the taskbar:
Open Taskbar and Start Menu Properties by clicking the Start button, clicking Control Panel, clicking Personalization, and then clicking Taskbar and Start Menu.
On the Taskbar tab, under Taskbar appearance, select "Never combine from the Taskbar buttons menu", and then click OK.