It’s annoyed me for a long time that when you’re using the Caja file manager in Linux Mint’s MATE desktop, the “Open With…” dialog is broken. I often want to open a folder in VLC and every time I have to select other… then scroll through the list and select VLC. It never “remembers” the association as an alternative for folders.
The fix is to edit the file ~/.local/share/applications/mimeapps.list and add the following line in the “Added Associations” section:
[Added Associations]
inode/directory=vlc.desktop;
And restart Caja to force a re-read of the file.
$ killall caja