There is an issue in AC8 v3 where certain details can not be deleted or renamed. Graphisoft Tech Support has provided a solution.
I have fixed the templates, so this shouldn't be a problem for new projects, but I'm sure there are some running projects that need to be fixed.
Laszlo Nagy sez:
"The detail was created in a Teamwork Project by a Team member, then the file was saved as PLN. Then the PLN file was opened as Solo Project and that's when those details created by the team member in the Teamwork Project could not be deleted."
The fix:
1. Share the offending project file. Sign in as Team Leader with exclusive access. Sign out.
2. Sign into that PLP as a Team Member. Reserve any workspace, skipping the Details. One layer on one story will do.
3. Save As Solo Project. Keep the name the same.
4. Upon opening that project, the details will be normal. Replace the old PLN with the new one.
Remember that when Saving As Solo Project from a Teamwork file, you are still in the Teamwork file; the PLN is saved to the side. You must close and open the PLN.
The sharing you're doing here is purely therapeutic; there is no need to concern yourself with sending changes.