Steps to recreate:
- Enable hovercards as a beta feature
- Enable navigational popups as a gadget (Go to preferences go to gadgets and tick "Navigation popups")
- Hover over any link
Expected behavior: navigational popup appears
Observed behavior: page preview and navigational popup appear
Note: easiest solution might be to add a note similar to the user preferences version: "Certain gadgets and other customisations May Affect the performance of this feature. If you experience problems please review your gadget and user scripts."