"Unable to delete the objects" pop-up when deleting class
Every so often I encounter this pop-up when trying to delete a class, and have never really understood the context of why it sometimes appears and sometimes doesn't.
The message seems to suggest that the class is being used by a Plug-in Object, but I know this isn't the case because typically it's a class I've made myself and it hasn't been used in any special way.
Today I finally realized the circumstances that cause this pop-up: objects in that class are be
If you open a new blank file + create a default unstyled Landscape area then immediately delete it + any resources which came with it (a line type?) you have a file with no objects + no resources in the RM. All that remains of the LA are the 'Site-DTM-Modifier' class (which you can delete) + the 'Site-Landscape Area-Spec' class (which you can't.) In order to delete the '-Spec' class you first have to run Purge with 'Special record formats' enabled. After purging the file of this format you are t