Whenever you make changes that affect Store Pages, ShopSite will need to regenerate the affected pages before the changes will be visible to customers. ShopSite will notify you when you make changes that require the pages to be regenerated, but the updates will not actually be made until you tell ShopSite to publish them. This allows you to make multiple changes in the back office, and then update the site all at once.
ShopSite Help - Publish Screen Configuration