This feature is available in Enterprise and Ultimate editions.
Using Project Workspaces, you can customize the user interface for each asset by choosing the fields and list values that display for each project or group of projects. A project workspace will include settings for all configurable fields of all project assets.
Project workspaces may be created for any project. The root/system project always has a project workspace; this workspace may not be deleted. If a project does not define its own project workspace, then it will follow the nearest workspace defined in its parent project hierarchy. Therefore, creating a project workspace will affect the existing project and all child projects that do not define their own workspaces.
Global assets are those that are not project-specific. This list includes Members, Projects, Sprint/Iterations and Change Sets. These assets can be customized to change the fields displayed. Any changes made will apply to these items globally across the entire system.