Is there a specific reason why your current setup has a close button rather than a cancel button? A cancel button would roll back the newly created objects so that you don't see the newly created, but uncommited objects in your overview pages after you close the page.
However, I'm just making assumptions about your page setup so please provide more infos how your page is currently set up, when the objects are created, where they are closed etc.
Hi Erupa,
Do you have any commit action to the any object which is associated to main entity used in the popup?
Ensure you are not committing any objects before the user clicks yes or no.