Thanks Bradvin and Luke. I found the solution. It was to uncheck “Automatically add paragraphs” in the text widget. 🙂
It is a shortcode in a text widget. I have added code to the functions.php so shortcodes can be used in a text widget.
I tried a different Gallery Template and it showed up in that widget area (without touching the shortcode or choosing another gallery) – it seems to just be an issue with the Owl Carousel.
The theme is Showcase Pro (a Genesis child theme).
