Hello.
Thank you for additional info. As for "
It appears that the "Select only published" option of the scrolling news item isn't working correctly as it shows all of my news items whether published or not." - I tested it on my default 5.5 version and Scrolling news web part behaves properly as per value of "Select only published" property. What is your version of Kentico
CMS, please? If you see news items in your web part, which are not published, it may have 2 reasons - you are not on Live site, but in Preview mode only, or the previous version of file under workflow is used. Could you please check these options? Thank you.
Best Regards,
Radek Macalik