With Jedit 4.5.2 I can open directories and files. Then someone decided to remove the OS/2 code from version 5.0. I did complaint, now OS/2 code is partial back in version 5.1, but that version can't open directories and doesn't see any files. If you give the drive, directory and file it will generate an error.
To me, insert the code which you took out in the first place. In version 4.5.2 it works, in version 5.1 it doesn't.