This is a split from #13495 as it is truly a separate issue. Here's a partial quote from msg151278:

"""
IDLE 3 no longer allows for editing of new files from the command line. 

For example:

   idle -e /tmp/newfile.py 

will momentarily flash an editor window before it is closed. This is due to "good_load" not being set. What's worse is that the IDLE process will continue running without having any visible windows open. 
"""

Rather than remove the good_load behavior as was done in an earlier patch in #13495, I added an extra line in the initialization logic so that the editor can edit newly named files while still rejecting files that didn't load properly.