How to disable tkinter listbox during a function - python-3.x

Question

I have a GUI created in Python 3.x using tkinter from Visual Studio 2017 Community. A top widget is created and within it a frame and listbox are added. When the user clicks on an entry in the listbox the index of the selection is passed to twoSecondFunction() which takes around 2 seconds to complete.
How can I stop the user from making another selection during this time?
I have tried using the line myListbox.config(state=tkinter.DISABLED) to disable the listbox when a selection has been made and only enabling the listbox again once the twoSecondFunction() has completed.
When I run the code from Visual Studio myListbox click events are handled by myListboxSelection and 'twoSecondFunction()' and print() are called. The window appears to be unresponsive for the duration of the myListboxSelection().
if the user clicks on another entry before
Function finished
has been output myListboxSelection() is called another time.
I can queue over 10 commands by clicking quickly before "Function finished" is output. The GUI appears unresponsive for the duration of all queued events and only responds to other commands after executing all the queued myListboxSelection() calls.
I have tried removing the line myListbox.config(state=tkinter.NORMAL) and this then registers only one click for the duration of the program, so myListbox.config(state=tkinter.DISABLED) is working as it should when it is called. myListbox also greys out.
I have also added extra print() lines throughout the program to ensure all operations happen in the expected order which they do.
It seems as though the logic executes a lot more quickly than the GUI itself responds, so myListbox becomes enabled far more quickly than the GUI responds. I do not see myListbox grey out during the execution of 'twoSecondFunction()'.
Is it because the myListbox.config(state=tkinter.DISABLED) only takes effect after the event handler completes its execution? I.e. myListbox.config(state=tkinter.DISABLED) never takes effect because myListbox.config(state=tkinter.NORMAL) is set before myListbox is actually disabled?
import tkinter #For the GUI tools
#Event handler for mouse click of myListbox
def myListboxSelection(event):
myListbox.config(state=tkinter.DISABLED) #Disable myListbox
myListboxIndex = int(myListbox.curselection()[0]) #Get selection index
twoSecondFunction(myListboxIndex) #Call function that takes 2 seconds
print("Function finished") #Output to console on completion
myListbox.config(state=tkinter.NORMAL) #Enable Listbox
#Create GUI
GUITopWidget = tkinter.Tk(screenName = "myListboxGUI") #Create Top Level Widget
myFrame = tkinter.Frame(GUITopWidget, name = "myFrame") #Create frame
myFrame.pack() #Pass to Geometry Manager
myListbox = tkinter.Listbox(authoritiesListFrame) #Create myListbox
myListbox.bind('<<ListboxSelect>>', myListboxSelection) #Bind mouse click event
populateListbox(myListbox) #Add entries to the listbox
myListbox.pack() #Pass to Geometry Manager
#Run the GUI loop
GUITopWidget.mainloop()

Answer 1

It appears that if you have an event handler and use mainloop() it does indeed stop any logic from executing during the callback. Instead define a loop which can handle the event calls, other logic and call update() on the GUI manually:
import tkinter #For the GUI tools
rootWindowClosed = False
requestQueued = False #True request is queued
myListboxIndex= -1 #Set to -1 between requests
#Event handler for mouse click of myListbox
def myListboxSelection(event):
myListbox.config(state=tkinter.DISABLED) #Disable myListbox
myListboxIndex = int(myListbox.curselection()[0]) #Get selection index
#On closing of root window
def closeGUIHandler():
#Set the rootWindowClosed flag to True
global rootWindowClosed
rootWindowClosed = True
#Destroy GUI Root
GUITopWidget.destroy()
#Create GUI
GUITopWidget = tkinter.Tk(screenName = "myListboxGUI") #Create Top Level Widget
GUITopWidget.protocol("WM_DELETE_WINDOW", closeGUIHandler) #Set delete window protocol
myFrame = tkinter.Frame(GUITopWidget, name = "myFrame") #Create frame
myFrame.pack() #Pass to Geometry Manager
myListbox = tkinter.Listbox(authoritiesListFrame) #Create myListbox
myListbox.bind('<<ListboxSelect>>', myListboxSelection) #Bind mouse click event
populateListbox(myListbox) #Add entries to the listbox
myListbox.pack() #Pass to Geometry Manager
#Run the GUI loop
while rootWindowClosed == False:
#If requestQueued then execute queued request
if requestQueued == True:
twoSecondFunction(myListboxIndex) #Call function that takes 2 seconds
myListbox.config(state=tkinter.NORMAL) #Enable Listbox
myListboxIndex = -1
#Update GUI window if not closed
time.sleep(0.05) #Sleep for 50 ms to allow event handling before executing code
if rootWindowClosed == False:
GUIRootWidget.update()