I can open items from the command line like so:
/home/me/FileNamePath$ java -jar /home/me/directory/jsamplerantasia-0.9.jar FileName.lscp
I also have some special dialogs in my file manager that execute this command. JSampler and LinuxSampler start-up and open the lscp file as expected.
What is not expected:
When I click on "Export"->"Sampler Configuration" the JSampler opens a dialog and tries to save
where /home/me/SomeOtherFileNamePath/SomeOtherFileName.lscp is the previous path and filename saved by JSampler.
This is mildly inconvenient for the user, and it also makes it more likely that the user will unintentionally overwrite SomeOtherFileName.lscp with FileName.lscp.