Cause of Tkinter error when displaying matplotlib graphs using PySimpleGUI - matplotlib

Question

I am currently developing a GUI in Python using PySimpleGUI and am working on plotting some graphs in frames contained by the main window. I succeeded in doing this using this example code1 and it looks fine. However, when I close the main window after having plotted a graph, I get the following list of errors related to Tkinter:
Exception in Tkinter callback\
Traceback (most recent call last):\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 1705, in __call__\
return self.func(*args)\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 3072, in set\
self.tk.call(self._w, 'set', first, last)\
_tkinter.TclError: invalid command name\ ".!toplevel.!frame.!notebook.!frame4.!frame4.!tkscrollableframe.!scrollbar2"\
Exception in Tkinter callback\
Traceback (most recent call last):\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 1705, in __call__\
return self.func(*args)\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 3072, in set\
self.tk.call(self._w, 'set', first, last)\
_tkinter.TclError: invalid command name\ ".!toplevel.!frame.!notebook.!frame4.!frame4.!tkscrollableframe.!scrollbar"\
Exception in Tkinter callback\
Traceback (most recent call last):\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 1705, in __call__\
return self.func(*args)\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 3072, in set\
self.tk.call(self._w, 'set', first, last)\
_tkinter.TclError: invalid command name\ ".!toplevel.!frame.!notebook.!frame4.!frame4.!tkscrollableframe.!scrollbar2"\
Exception in Tkinter callback\
Traceback (most recent call last):\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 1705, in __call__\
return self.func(*args)\
File "/usr/lib64/python3.6/tkinter/__init__.py", line 3072, in set\
self.tk.call(self._w, 'set', first, last)\
_tkinter.TclError: invalid command name\ ".!toplevel.!frame.!notebook.!frame4.!frame4.!tkscrollableframe.!scrollbar"\
I am new to matplotlib and haven't used Tkinter before, but would like to know the cause of these errors, if anyone knows. My code is quite big, but I can add it to the post if necessary.
I have tried commenting different parts of my code to find the culprit and when I remove the line corresponding to the following in the demo I used, the errors stopped:
figure_canvas_agg = FigureCanvasTkAgg(figure, canvas)
Have anyone experienced this problem before? I am running this on a machine running Centos and have tried running a simpler program in Windows, which closes without any problem.
Thanks in advance.
EDIT 1: Upon request I have just added the simplest Python code I could produce that reproduces this kind of error:
import PySimpleGUI as sg
import matplotlib as mp
from matplotlib import figure
from matplotlib.backends import backend_tkagg
import numpy as np
layout1 = [
[
sg.Frame("Frame",
[
[
sg.Column(
[
[sg.Canvas(key="-CANVAS-")]
],
size=(1000,1000)
)
]
]
)
]
]
layout2 = [
[sg.Column(layout1, scrollable=True)]
]
window = sg.Window("Window", layout2)
window.finalize()
x = np.array(list(range(10)))
fig = figure.Figure()
ax = fig.add_axes((0,0,1,1))
ax.plot(x, x)
figure_canvas_tkagg = backend_tkagg.FigureCanvasTkAgg(fig, master=window["-CANVAS-"].TKCanvas)
figure_canvas_tkagg.draw()
figure_canvas_tkagg.get_tk_widget().pack()
while True:
event, values = window.read()
if event == sg.WINDOW_CLOSED:
break
window.close()
It appears that it might have something to do with the fact that my GUI code consists of many levels of container-objects within cointainer-objects. In my full code I have a couple of layers on top of this, but the error seemed to appear once I made the following hierarchy:
Column
Frame
Column
Canvas
It should be noted that using the debugger of Visual Studio Code I have found out that the error does not occur exactly when the window closes (when the window.close() method is called), but some time before.
EDIT 2: I just tested it and for some reason this error only occurs when I run the attached Python script on my Centos machine and not in Windows.
EDIT 3: I found out that if I close all the figures I have created before I close the window, these errors will not occur. This is not a complete fix however, since the error occur before the window.close() command of PySimpleGUI is run, so I don't know where to put the code that would close the figures in case the window is closed.