When opening a file, pcmanfm should not treat it as an URL even if there is a %u/U in the application description. It should consider %u/%U as %f/%F if it's a local file.
For example when opening a file named diagram in draw.io, that has the command
/opt/drawio/drawio %U
it fails to open and give the message "No such file or directory : 'file:///.../diagram'
It works when opening it on another file manager, or typing in terminal drawio /.../diagram
Anonymous