Adding to the list of annoyances, “Preferred Applications” does not save changes nor does it have a button to save. Some seem to save, but most don’t.
In particular, if you have Only Office and TextMaker installed, no matter how hard you try you cannot get the default spreadsheet application to change to TextMaker and stay there.
Adding insult to injury the “Document Viewer” is really busted for PDF handling. No matter how hard you try you cannot change this to Opera (which actually works) and have it stick.
Is there a command line method of changing these that will actually stick.