https://sourceforge.net/apps/trac/sourceforge/ticket/12983
On the main project's tools page, "Delete" does not remove subprojects from the list.
Tested on my test project, after deleting the "polkadots" subproject, I still see it listed here (not expected): https://sourceforge.net/p/fancypants/admin/tools
But, as expected, the subproject isn't available if I try visiting it: https://sourceforge.net/p/fancypants/polkadots/home/
I'm not able to reproduce this anymore. If there's something not working now, can you re-open the ticket with another example?