Renaming a Configuration actually creates a Copy

  1. right-click the project’s name in the Project Explorer
  2. choose Build Configurations > Manage…
  3. use the ‘Rename…’ button to rename the active configuration
  4. OK

A copy of the “renamed” i [/i]configuration appears in the Project Explorer in addition to the configuration with the original name!

So it’s just done a copy - not a rename!

However, returning to the ‘Manage Configurations’ dialogue, it contains only the renamed version - not the original!

So there’s this “orphan” configuration folder left in the Project Explorer!

If you rename a configuration other than the Active one, it’s worse:

the Project Explorer is not updated at all - so you still see the old name, and there’s no sign of the new name!

Actually, the inner configuration object is indeed renamed (no duplication at this level). But it’s true that the build configuration output folder itself is not renamed (and then a new one with the new config name is created).
The build configurations rename facility is implemented in the Eclipse CDT core.

About the non-active configs, the new folder is not created since these output folders are created only when the corresponding configuration is active. E.g. when you create a project, only the active configuration folder is created, not the other ones.

But, when you create a New configuration in an existing project, its output folder does appear in the Project Explorer, but it doesn’t appear in the ‘Manage Configurations’ list until you close and re-open it!

The explanation of this strange behaviour:
we have indeed a known GUI bug in the Manage Configurations list, which doesn’t display newly created configs until the dialog is re-opened. But since the newly created config is immediatly set as the active one, its output folder is then created on the Project Explorer.