Terry J. Reedy added the comment:
This is purely a tkinter issue. Windows people can ignore this.
Your problem was a result of your program error, of not keeping a reference to
Tk(), combined with tkinter's _default_root 'feature'.
The solution you report in your answer, 'root = tkinter.Tk()'
New submission from Philipp:
Today I ran into a problem when using both tkinter and matplotlib.pyplot at the
same time. I thought it would be best to let you know, in case it is an issue.
The problem is/was that the root window did not close itself, when just using
`askopenfilename()`.
A co
