Standalone Image Viewer, Behaviour

I have a directory with file types PDF, EML and JPG. First file is PDF. I mark it in DOpus and hit F7. The viewer window shows the PDF. When I now click on fullscreen view, the standalone viewer opens and shows the first file that has file type 'image' (here: JPG). If a directory does not contain images, it shows the selected document in a separate window (that is what I want). How can I change this behaviour so the standalone viewer just shows the selected file?

Directory Opus Pro 12.15 Build 7102 x64
OS 6.1 (B:7601 P:2 T:1) SP 1.0 "Service Pack 1"

Thanks,
Peter.

Thanks for the report, we'll fix this in the next update.

The latest beta is out now and has the fix for this.