If you try to delete a folder in the project dock, but don't have enough rights to do so, kdevelop simply let the folder disappear. Therefore the user thinks the folder is deleted but in fact it is not. It would be nice if kdevelop would tell the user that it doesn't have enough rights (as dolphin does).
It works for me. I get a message box and it doesn't go anywhere. Can you specify what project type we're talking about?