Developer PCMan is a medical student and hence a busy man. This and other reasons resulted in PCManFM being poorly maintained.
Developer ignorantguru took up the lead and developed SpaceFM, a worthy and more powerful successor to PCManFM. SpaceFM features many easily installable user-contributed plugins —some of yours truly— that will cater for many of your needs.
Follow the instructions for installing SpaceFM on Ubuntu (and Debian).
After installation, run
exo-preferred-applications and choose
spacefm as the default file manager:
You also will have to change a few MIME defaults:
xdg-mime default spacefm.desktop inode/directory application
~/.local/share/applications/mimeapps.list should also be edited.
Look for the line containing
and change it to read
It is possible that you also will need to perform a similar edit of
/usr/share/applications/mimeinfo.cache under administrative rights.
mimeopen -a filename might be helpful in debugging MIME type settings.
If you are using XFCE like I do, there remains one caveat. Links on the desktop will continue to open with Thunar. (Thunar cannot be uninstalled because of other dependant packages.) It seems that this behaviour for opening desktop links is hard-wired in XFCE 4.8.