Disabling button while TextInputs have not had text input into them - PySimpleGUI

I am writing a simple GUI script using PySimpleGui and have been trying for a week to figure this out, but no amount of googling or trying various solutions seems to do what I want.

The gui is simple, it has two sg.InputText inputs, and one sg.Mulitline input. There is also an sg.Button that kicks off running a function, that takes the values of the 3 inputs as its arguments, when pressed. I would like to have the button be disabled out while the user has not entered any text into the input boxes, and re-enabled once they have. This will keep the user from being able to run the tool before they enter the required inputs. I have tried basic logic, but cant seem to get it to work.

Sample Code:

import PySimpleGUI as sg

inputs_column = [
    [sg.Text(text='Enter value 1'), sg.InputText()],

    [sg.Text(text='Enter value 2'), sg.InputText()],

    [sg.Text(text='Enter values 3')],
    [sg.Multiline(size=(60, 20), sbar_background_color="grey42", key="value_list")],

    [sg.Button('Start', disabled=True), sg.Button('Quit')]
]

layout = [[sg.Column(inputs_column)]]

# Create the Window
window = sg.Window('Fancy Doo-hickey', layout)

# Event Loop to process "events" and get the "values" of the inputs
while True:
    event, values = window.read()

    # kill the process if user closes window or clicks cancel
    if event == sg.WIN_CLOSED or event == 'Quit':
        break

    # what to do when the start button is pressed
    if event == "Start":
        # turn the values given by the user input into a list
        value_list = values['value_list'].strip().splitlines()
        
        # check to see if user has given input yet
        while values[0] == '' and values[1] == '' and len(value_list) == 0:
            window['Start'].update(disabled=True)
        else:
            window['Start'].update(disabled=False)

        # run the main function
        run_function(arg1=values[0], arg2=values[1], arg3=value_list)

Any ideas? Is it even possible for PySimpleGUI to monitor what is entered into the TextInput boxes before an event is triggered?

Any help is much appreciated.

Need to generate an event when the content of element changed, so add one more option enable_events=True, and handle that event to decide if disable the button or not.

Reduced code as following.

import PySimpleGUI as sg

def func(*args):
        print(*tuple(map(repr, args)))

layout = [
    [sg.Input(enable_events=True, key='IN 1')],
    [sg.Input(enable_events=True, key='IN 2')],
    [sg.Multiline(size=(40, 5), enable_events=True, expand_x=True, key='IN 3')],
    [sg.Push(), sg.Button('Start', disabled=True)],
]
window = sg.Window('Demo', layout)

while True:

    event, values = window.read()

    if event == sg.WIN_CLOSED:
        break

    elif event in ('IN 1', 'IN 2', 'IN 3'):
        disabled = not (values['IN 1'] and values['IN 2'] and values['IN 3'])
        window['Start'].update(disabled=disabled)

    elif event == 'Start':
        func(values['IN 1'], values['IN 2'], values['IN 3'])

window.close()