Symptom
Clicking an item navigates to the post, although Click Action is set to Popup.
Cause
A post opens in the lightbox only when it carries something the lightbox can show: a featured image, or the Video format with a Video URL. With Pro it can also be the Audio format, a Gallery, or a custom media set on the project.
A Media item behaves differently: when its own settings hold a custom URL, the item always links out, whatever the Click Action says.
Fix
- Set a featured image on the project, or give it a format with its media filled in. See Project Formats.
- For a Media item, clear the custom URL in the item’s settings.
The setting itself is described on Click Action.