Bing announced a new feature within the Bing Ads Editor. It now supports managing your account level ad extension associations from Bing Ads Editor. Bing is starting with managing specifically the Callout Extensions.
Bing promises they will continue to "add support for account level ad extension associations for the remaining ad extensions in our future releases."
Account level association for ad extensions allows you to add and edit ad extensions at the account level. This new feature can help save you time and provide consistency across advertising platforms. And now you can manage them in Bing Ads Editor. This specific capability is unique among desktop search marketing tools. Associating ad extensions at the account level ensures that your ad extensions apply automatically to all existing and new campaigns, helping to improve performance and return on the existing ads.
Forum discussion at Twitter.