Configuration Editor
The Configuration Editor is displayed using the Project | Configuration | Edit… menu item and supports the following operations:

Remove
Remove the selected configuration. If it was the active config, then the next one in the list is made active.
Rename
Rename the selected configuration.
Add…
Add a new configuration. The Add Configuration dialog allows specifying an existing configuration to use as a template.
Make Active
Makes the selected configuration active.
Close
Exits the configuration editor