Project Server 2010 includes the new Project Permission feature so that by-default, Project Managers can directly control who has access to the projects that they own. For more information about the Project Permissions feature, see the Project Server 2010 – Project Permissions blog posting.
The ability to directly add or remove permissions to a project is controlled by the Manage Basic Project Security category permission. Given that this is a category permission, it means that it is possible to grant this permission for one project yet deny it for another project or more commonly, to grant it for a group of projects yet deny it for a different group of projects.
By default, the following groups have the Manage Basic Project Security permission enabled on the noted category:
Group
Category
Administrators
My Organization
Portfolio Manager
Project Managers
My Projects
How do you enable or disable this permission? The following steps show you how you could, for example, deny Portfolio Managers from creating project permissions. A similar approach is taken to enable or remove the permission for a group or user.
As noted, you can use a similar process to add the Manage Basic Project Security permission to other users or groups. But do note that that though you can control this permission directly on a category on a user account, for easier manageability it is recommended that you control this at the security group level.
I need to Know, How to go back the original conditions about the global permissions?