When I enter, for instance,
xdg-mime query filetype Video/movie.mkv, the output is
video/x-matroska; if I then enter
xdg-mime query default video/x-matroska, the output is
mplayer.desktop, and that is indeed the application used when I enter
xdg-open Video/movie.mkv. The same holds for other filetypes for which I've set specific default applications.
On the other hand, nothing happens when I click on "Open Dropbox Folder" in Dropbox' tray icon popup menu, or when I do right-click and "Open folder" on a file in Transmission's list of downloaded files; so, I would expect that no application is associated with directories.
With this in mind, what I've tried so far is to run
xdg-mime query filetype Video, which returns
inode/directory and, in turn, run
xdg-mime query default inode/directory, which returns
ranger.desktop, my file manager. This sounds quite what I would have expected if everything worked, but this is not the case.
Why nothing happens when I click on "open folder" et similia in popup menus?