Sounds like a pointer to something inside your script is left active after your script ends.
Background: Python is allways active and any script started is working in the same Python namespace. There is no "reset" after your script stops.

Try this: Start any script (probably one using a listbox). Exit the script. Create and run a new script containing:

**print "LEFT OVERS"
print "Globalsn",globals()

**You will see a list of objects/variables left over from the previously started script.

Better use classes. If you declare most of your script in class myApp, after

root=Tk()
app=myApp(root)
root.mainloop()
del app
del root

All your objects should be deleted via Pythons garbage collector.

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