Eryk: If one wants a shortcut on the desktop, I believe the one in a directory has to be copied.  I was also trying to cover the case where IDLE is installed for all users and a particular user wants a customized shortcut.

Steve: Microsoft's effort to keep most users ignorant of command lines has been all too successful.  So a new C.L. option can only be part of a solution.

It seems that IDLE automatically changing directory, under some circumstances on some systems, to ???, should be part of a solution.
But Documents is better that HOME.  (This is the default now on Mac.)

Last week there was a discussion of this issue started by someone who teaches or supports Python for non-computer experts at a university with multiple computers around the campus networked to a central computer with installed Python.  What he and others want is for IDLE to start in a particular user's Python scripts subdirectory, and not have to change the directory in the open file dialog. This will require a new config option.  

For a config option to work with repository python (at least for me), I would like python.bat to the repository directory that contains /Lib rather than merely set PYTHONHOME to same.

I need to make a list a ways to start Python and the consequences for sys.path and current directory on the three major systems and add it to idlelib/README.txt.  For this issue, there are also ways to open a file after IDLE is started.