Deleting unwanted foreign currencies

I've religiously followed the instructions below to delete unwanted currencies from the 4 page list 

but no matter what I do whether I have turn on live exchange rates ticked or unticked it won't let me delete anything.  Would someone please address this

Highlight the currency you wish to delete from the list.

Press the Delete key on your keyboard.

Confirm Deletion: A confirmation message will appear.  Click Yes to permanently delete the currency