I have DOpus set to open PDFs with PDF-XChange Editor. I've double checked this in Settings/File Types, and it's set correctly. In Windows I also have PDF-XChange Editor set to the default app for opening PDF files. In Windows Explorer this works fine, but whenever I go to the open a PDF by double clicking on it, Photoshop opens up. It can't open the file, so it doesn't display anything, just opens to the default PS screen. I've searched through the File Types dialog for all file types set to open with PS, and there's quite a few of them, but PDF is not one of them.
Any guidance as to how I might fix this?