Hello,
I would like to report what I believe is a bug and will add unwanted duplicates.
When in the field to add a past sale and then for example the auction is not listed I select the web button to return a page and then add the Numista sheet but this then actually adds the same sheet for a second time.
Maybe on the top of add a past sale page you should implement a button to cancel and then the Numista sheet gets added without adding the past sale.

