Deleting CiviContribute Campaign Pages and Premiums

Trying to delete default content that comes with CiviCRM, I could not delete the Mug Premium even after deleting the "Contribution Page - Help Support CiviCRM!" and all other Online Contribution Pages, as CiviContribute says it is still being used on an Online Contribution Page.

I thought I would test it on the demo site. Going to the Demo site I couldn't delete the "Contribution Page - Help Support CiviCRM!" which is the only one with the Mug Premium. CiviContribute says there is a contribution that has been made using "Contribution Page - Help Support CiviCRM!" Online Contribution Page and when I try and delete that Online Contribution Page I get the message:

".... If you do want to completely delete this contribution page, you first need to search for and delete all of the contribution transactions associated with this page in CiviContribute."

So I searched for and deleted all contributions using the "Contribution Page - Help Support CiviCRM!" online contribution page on the demo site and I still can't delete the contribution.

So it seems there are two bugs, one that won't let you delete an Online Contribution Page even after you have deleted all contributions associated with it, and one that won't let you delete a Premium even after you have deleted all Online Contribution Pages associated with it (I couldn't replicate the later on the demo site because of the former).