Na verdade, eu segui as etapas descritas aqui .
To implement the new behavior, follow the following registry trick:
- Open Microsoft Visio.
- Go to Tools -> Options -> Advanced.
- Check the Put all settings in Windows Registry option.
- Run Registry Editor (regedit).
Navigate to the following registry key:
HKEY_CURRENT_USER\Software\Microsoft\Office.0\Visio\Application\In the right pane, right click on SingleInstanceFileOpen, and then select Modify. Update the value of SingleInstanceFileOpen from 1 to 0.
Mas a chave estava faltando na minha máquina, então eu adicionei e reiniciei a máquina. Agora parece trabalho.