The permissions settings of projects are a bit different from the wiki and blog post ones.
You can select what roles can create projects by front end, but there is not an option for editing. The reason is that, by default, the projects are editable by:
- All members assigned to the project itself;
- Author of the project;
- Administrators.
During the creation of a projects, the creator can disallow the members of the projects to edit it. So only he and the administrators will be able to edit it. To do this, the user have to check this option during the process of project creation: