The file manager PCManFM has an option (enabled by default) to ask what to do with inserted/mounted volumes (cd, dvds, iso files etc) which is lacking in elementry OS' file manager. That's why I m using PCManFM for this purpose.
When connecting an external HDD:
When inserting a DVD or mounting an iso-dvd:
When inserting a CD:
But can that list be edited somehow in order to add or remove items?
Update after answer:
/.local/share/applications/mimeapps.list contains this:
[Default Applications]
x-scheme-handler/apt=apturl.desktop
xdg-mime default org.pantheon.appcenter.desktop x-scheme-handler/apt
No [Added Associations] , nor x-content/audio-cdda.
Possibly an elementary-os-specific issue?




[Added Associations]Belowx-content/video-dvd=your Programmandx-content/audio-cdda=your Programm.Afterupdate-mime-database $HOME/.local/share/mime– Dec 05 '16 at 11:19x-content/video-dvd=xine.desktop;totem.desktop;brasero-copy-medium.desktopI can open Video-DVDs, with these Programs. But my Standart_program isx-content/video-dvd=mpv-dvd.desktopThis desktop file I create by my own.xdg-mime query default x-content/video-dvd mpv-dvd.desktopI clear with my answer my kontext-menu from clamtk, because it would open my compressed files by default. And it was almost bei all data in the Kontext-menu. I hoped it did help you too. – Dec 05 '16 at 14:49mimeapps.listis not the same in all cases; the same may be true for the location of desktop files, and for the path in the commandupdate-mime-database. By pure chance I have found on one of my systems the file~/.config/mimeapps.list. Addingx-content/audio-cdda=deadbeef.desktopin there, Deadbeef appears in the pop-up list for cd. – Dec 05 '16 at 16:34mimeapps.listfile: https://wiki.archlinux.org/index.php/default_applications#XDG_standard – Dec 05 '16 at 17:13