Why can a manager user not create or edit projects, portfolios, pools or resources?
The user level of a manager only denotes his or her “maximum” permission level for a business object. Permissions themselves are defined on the per-project, resource etc. level. Before a manager can create or edit a project, portfolio etc. he needs to be given the appropriate permissions for the project, portfolio etc. in question. For instance, in order that a user can create a new project, he or she must be given manager or administrator permissions for the portfolio the project is to be created in. You are doing this on the “Permissions” tab of the “Edit Portfolio” dialog.