LMDE 201403 Cinnamon 64 bit
UPDATED to spell out problem a bit more, and the solution.
I have installed Okular and it has extra function to that provided by Document Viewer, the default PDF file viewer on my LMDE system.
If I double-click a PDF file, Document Viewer opens it. If I right click on a PDF file, the first option is to open with Document Viewer, The second option on a right click is to Open with
- Print Preview
- Other application
If I select Okular the file opens fine, but the default stays as Document Viewer.
If I select Other application it opens another window called 'Open With' which allows me to set a different default.
The Open With window shows
- Default : Document Viewer
- Recommended : GIMP
- Other : a list of apps which however does NOT include Okular, nor in fact Print Preview both of which are secondary 'open with' apps as shown above
I tried to add Okular to the list (I assumed of Other apps) but it didn't work. That's because the list it refers to is the list of secondary 'open with' apps, I discovered. I cleaned that up by resetting to System Default.
However when I specified Okular and clicked on 'Set as default' it worked fine.
I now have Okular as the default PDF file viewer. That is, first choice on right click, or when I double-click, Okular opens PDF file.
I'm leaving this thread in the forums, as it may be useful to another newbie !