Apologies if this is some basic error or lack of information on my part; I have been reading SO and open desktop specs and have tried many combinations and can't figure out what I'm doing wrong. If I am doing something wrong I've not been able to find documentation to correct me.

qtfm overwrites my~/.config/mimeapps.list (or~/.local/share/applications/mimeapps.list if I use that location).

• Every time I attempted to make a change I made sureqtfm was not running while I edited any files
• I confirmed thatqtfm preferences were set to read the rightmimeapps.list location
• I removed allmimeapps.cache files that I found
• I removed alldefaults.list files that I could find

And still I got the following behaviour:

1. Ensure~/.config/mimeapps.list hasmupdf.desktop as the first entry forapplication/pdf mimetype
2. Startqtfm and open a PDF file - Master PDF editor is used instead
3. Exitqtfm and findmimeapps.list has changed to removemupdf.desktop entry

Expected behaviour:

1. Ensure~/.config/mimeapps.list hasmupdf.desktop as the first entry forapplication/pdf mimetype
2. Startqtfm and open a PDF file - MuPDF application is used
3. Exitqtfm and findmimeapps.list has not changed

To be clear, the sequence is shown inbash here:

$ grep mupdf ~/.config/mimeapps.list$ vim ~/.config/mimeapps.list$ grep mupdf ~/.config/mimeapps.listapplication/pdf=mupdf.desktop;masterpdfeditor4.desktop;chromium.desktop;gimp.desktop$ sudo update-desktop-database$ xdg-mime query default application/pdfmupdf.desktop$ qtfm$ grep mupdf ~/.config/mimeapps.list$ xdg-mime query default application/pdfmasterpdfeditor4.desktop

It appears that QtFM overwrites themimeapps file on start up, but it's not clear where it takes the default file or entries that it uses to overwrite this file. Apologies if I misunderstand basic desktop usage but it was my expectation that applications should not write to this file (unless requested as part of user configuration).

If I try to use QtFM as the means to update my defaults, by usingEdit > Settings > Mime Types, QtFM apparently only draws on that file for candidate applications, and it only does soafter it has over-written the file. It does not refer to/usr/share/applications/, so the user can only change the order of the applications already in use for that particular mime type (within the over-written file, not as originally found in the file by QtFM on start up). Althoughmupdf.desktop is available in/usr/share/applications, sincemupdf.desktop has been removed by QtFM from themimeapps file, MuPDF is no longer available for use in QtFM Mime Type settings.

It does appear that QtFM over-writes the configuredmimeapps.list file on start up. QtFM specifically over-writes the file that it is configured to read, to learn what the user defaults are, as set inEdit > Settings > Mime Types > Default mime applications Configuration file. It's not clear (to me) where QtFM gets it's authoritativemimeapps.list file from, as I have no othermimeapps.list ordefaults.list files (that I can find) on my system.

$ ag -u -g mimeapps /~/.config/mimeapps.list$ ag -u -g defaults.list /

Could you please either clarify what I'm doing wrong here, or else fix QtFM to respect the standard properly?

If I'm doing something wrong, could you please clarify the correct usage in theman page or as appropriate?

Thanks