The list of program that is displayed when right-clicking on a file in PCManFM is the combination of: mimeinfo.cache mimeapps.list The default program that is launched when you double-click on a file in PCManFM is (first match wins): The one from ~/.local/share/applications/mimeapps.list The one from ~/.local/share/applications/defaults.list The one from /usr/local/share/applications/defaults.list The one from /usr/share/applications/defaults.list The first one from /usr/share/applications/mimeinfo.cache

From https://lkubaski.wordpress.com/2012/10/29/understanding-file-associations-in-lxde-and-pcmanfm/