PDF viewer not working

Using my Opera browser I can view embedded pdf articles on our current version, 2.4.8. On our test installation 3.101 when clicking on pdf I trigger a download instead of displaying the article. How can I fix this?

Hi @nickpanes,
Did you check if PDF.JS PDF Viewer is activated (in Plugins)?

Ugh – well that was easy. Cannot believe I missed it. Many thanks. Nick