I can not write English, sorry. I Hide the Ribbon in SharePoint so that users who do not have access to administrator does not show, and that's settled, what happens now that does not show the user's name and can not leave the session.
How I can redisplay only part of the session?
Image with access to a group and the user's name is not visible.
To display Username try this
<wssuc:Welcome id="IdWelcome" runat="server" EnableViewState="false">
Copy and paste the above line anywhere inside a placeholder in the master page. You can also try security trimmed control in sharepoint master page (Manageweb etc) Google it