I’m on Ubuntu. The default PDF reader was Document Viewer, but I changed it to Okular. When I right click on a PDF file in Obsidian and select “open in default app”, it still uses Document Viewer.
I searched for “default app” “pdf” and a few other search options. I didn’t see anyone having this same issue.
I have tried locating PDF files in my Obsidian Vault using the Ubuntu file explorer and opening them by double clicking, to confirm that Okular is the system default.
I tried rebooting my system, but I still see the behavior described above.