Xselect supports multiple sessions in the same directory, and even simultaneously, provided they have distinct names. On entry into Xselect, you will be prompted for a session name. Then all the product files written out by Xselect will have this session name as a prefix. The default session name is xsel. So for instance the light curve output qdp file is called xsel_curve.xsl. You can also enter the session name when launching Xselect:
% xselect prefix=myown
will start up a session with the name myown.
When you exit Xselect, you are prompted whether you wish to save the session or not. If you respond yes, all the temporary files are saved, otherwise they are all removed. Do not erase any of these files on your own if you wish to restore the session at a later date.
To recall a saved session, simply give the same name at the session name prompt, and you will be prompted whether to restore the saved session. One caution, if you respond no to this prompt, the previous session will be cleared before Xselect proceeds and you will loose all the product files (except of course those you saved with your own filenames, with the save command).