This is a known error and applies to users of the Chrome browser.

Chrome users may experience that preview opens in the same tab as the source test, question, or question set.

This is caused by a pop-up blocker in Chrome, and is easily fixed. 

1. Go to the following address:

   chrome://settings/content/popups

2. Add the URL to your Inspera site to the allowed list in this format:

   https://demo.inspera.no

Note that the above is an example, and you must use the URL to your Inspera site for this to work.