Apparently the problem has something to do with the subprocess that Idle connects to. If I try to run the program by opening Idle, then editing the file and running it, I get nothing. However, if I right-click the file in the Explorer window and click Edit with Idle, my program can create and manage Tkinter windows. From what I read, this method launches Idle without a subprocess, hence my conjecture that I've done something to wreck Idle's ability...

no error msgs, nothing. All the Idle windows close down, as well as the Tkinter window I created. In a sense, this is presumably the correct behavior on encountering a quit, except for the part about not being able to open a new window in a new session.

I couldn't find a process or service with python or Tk in the process name. Could it have some oddball name I wouldn't recognize?

In my button handler I mistakenly typed quit() instead of root.quit() (where root is the window). This caused Idle to shut down (as one might expect). What I don't understand is that when I restart Idle Tkinter no longer will display windows. I have to reboot to clear whatever is wrong. I'm guessing I've orphaned some process related to Tkinter that Idle isn't connecting to, or some such.

How do I clear this state?
I'm running...