I'm unable to figure out why Firefox is opening PDF files in LibreOffice. This happens when I open the file in the downloads view (the little down area on the toolbar).
When I first click on a PDF it correctly asks me to save the file -- I've set this option in the preferences. But when I click to open the downloaded file it uses LibreOffice.
If I use Dolphin (KDE file browser) and click on the file it correctly opens the file with Okular.
I don't know where Firefox is getting the PDF -> LibreOffice association for downloaded files.
I've attempted the solutions listedn in Firefox application associations not working in the 'Downloads' window and they are not working for me.