When a UDT definition has instances and you go to delete it, it brings up a prompt warning you that it has instances and if you want to continue. If you press Esc to cancel it, it deletes it 
And tag deletions aren’t added to the undo stack…
When a UDT definition has instances and you go to delete it, it brings up a prompt warning you that it has instances and if you want to continue. If you press Esc to cancel it, it deletes it And tag deletions aren’t added to the undo stack…