I recently upgraded to Ubuntu 18.04.1 LTS, and some files no longer open correctly in their default applications (e.g. PDF and JPG files). Instead, Colibri opens with no content. I've confirmed their default application is set correctly (Document viewer for PDFs and Shotwell Viewer for JPGs) but they still open in Colibri. I can select 'open with' and choose the default application again, and they will open correctly.
I also found Clicking links in pdfs opened with Okular opens Abiword (instead of the default browser) whih looked similar and ran
kcmshell5 filetypes but everything seemed to be normal.
From command line - Open files only opens terminal instead of file browser I could check other mime-types, but I'm not sure what to look for.
What settings should I check for this default program problem?