Unable to Pin function in PysimpleGUI

I have a program adding and removing elements on the screen with + and - buttons, the problem is the fact that these buttons don't change position automatically after this change of display like I would expect when using pin function :

1- Initial situation (everything is fine)

2- Adding a frame (everything is fine)

3- Removing a frame (the buttons 'Add another requirement' and 'Remove a requirement' did not move)

Code for this layout :

def layout_specification_frame(lvl_1,lvl_2):
    layout = [[sg.Frame(title  = f'Specification N° {lvl_1}',
                        layout = [[sg.Text ('Name of the specification'),      # Layout for one specification 
                                   sg.Input(key    = ('-SPECIFICATION TITLE-', lvl_1)),
                                   sg.Text ('Select IFC Version:'),
                                   sg.Combo(ifc_versions, size=(20, 1),default_value='IFC4', key=('-VERSION-',lvl_1))],
                                  [sg.Frame(title  = 'Applicability',
                                            layout = [[sg.Text  ('All elements of'), 
                                                       sg.Combo (categories, default_value=None, enable_events=True, key=('-FACET-',lvl_1)),
                                                       sg.Text  ('That have a')],
                                                      [sg.Column(layout_parameter(category,lvl_1),key = f'-FACET PARAMETERS {lvl_1}-')]],
                                            key    = f'-APPLICABILITY {lvl_1}-',
                                            relief = 'sunken')],  
                                  [sg.Column(layout_requirement_frame(lvl_1,lvl_2),key = f'-SPEC REQUIREMENT {lvl_1}-')],
                                  [sg.pin(sg.Column([[sg.Button('Add another requirement', key = ('-ADD REQ-',lvl_1)),
                                                      sg.Button('Remove a requirement',key = ('-REMOVE REQ-',lvl_1))]]))]],
                        key    = ('-FRAME LVL 1-',lvl_1),
                        relief = 'groove')]]
    return layout

and in the window.read loop :

        elif event[0] == '-REMOVE REQ-' :
            lvl_2 = lvl_counter[event[1]]
            if lvl_2 >1:
                window[f'-REQUIREMENT {event[1],lvl_2}-'].update(visible = False)
                lvl_counter.update({event[1]:lvl_2-1})
                window.refresh()

Thank you for your time

Update to answer comments : (the code is quite big so I did not want to overload)

The element corresponding to this window[f'-REQUIREMENT {event[1],lvl_2}-'].update(visible = False)

is in the function called sg.Column(layout_requirement_frame(lvl_1,lvl_2),key = f'-SPEC REQUIREMENT {lvl_1}-')

That function is described here : (I also add the other function called inside so you can follow)

def layout_requirement_frame(lvl_1,lvl_2):
    layout = [[sg.Frame(title  = f'Requirement {lvl_2}',
                        layout = [[sg.Text ('Should have a  '),
                                   sg.Combo(categories_req, default_value=None, enable_events=True, key=('-FACET REQ-',lvl_1,lvl_2)),
                                   sg.Text ('With')],
                                  [sg.Column(layout_parameter_req(category_req,lvl_1,lvl_2),key = f'-REQ FACET PARAMETERS {lvl_1, lvl_2}-')]],
                        key    = f'-REQUIREMENT {lvl_1,lvl_2}-',
                        relief = 'sunken')]]
    return layout
    
def layout_parameter_req(category_req,lvl_1,lvl_2):
    cat = category_req[(lvl_1,lvl_2)]
    if cat == None :
        layout = [[]]
    else : 
        items  = Facets[cat]['facet_parameters']
        layout = [[sg.pin(sg.Frame(title  = '',
                                   layout = [[sg.Text  (item['name'], size=(15, 1)), 
                                              sg.Input (key = ('req',cat, item['name'],lvl_1,lvl_2)),
                                              sg.Text  ('Required' if item['required'] else 'Optional',font=('Helvetica', 12, 'bold' if item['required'] else '')),
                                              sg.Push  (), 
                                              sg.Button('+')]for item in items],
                                   key    = f'- FRAME REQ{cat,lvl_1,lvl_2}-',
                                   relief = 'flat'))]]
    return layout 

And the frame is added with an extend layout just there :

 elif event[0] == '-ADD REQ-' :
            
            categories_req  = categories.copy()
            if values[('-FACET-',event[1])]: 
                categories_req.remove(values[('-FACET-',event[1])])
            lvl_2 = lvl_counter[event[1]]+1 #retrieve the previous value (with the dict)
            category_req.update({(event[1],lvl_2):None})
            if f'-REQUIREMENT {event[1],lvl_2}-' in window.AllKeysDict:
                window[f'-REQUIREMENT {event[1],lvl_2}-'].update(visible = True)
                lvl_counter.update({event[1]:lvl_2})
            
            else : 
                lvl_counter.update({event[1]:lvl_2})
                window.extend_layout(window[f'-SPEC REQUIREMENT {event[1]}-'],layout_requirement_frame(event[1],lvl_2))
            window[('-FACET REQ-',event[1],lvl_2)].update(values=categories_req)

I cannot run your script to find what's wrong, but reduce and revise your code to following script and it work.

import PySimpleGUI as sg

def layout_specification_frame(lvl_1,lvl_2):
    sub_frame = [
        [sg.Text('All elements of'),
         sg.Text  ('That have a')],
        [sg.Column([],key = f'-FACET PARAMETERS {lvl_1}-')],
    ]
    column_layout = [
        [sg.Button('Add another requirement', key = ('-ADD REQ-',lvl_1)),
         sg.Button('Remove a requirement',key = ('-REMOVE REQ-',lvl_1))],
    ]
    frame_layout = [
        [sg.Text ('Name of the specification'),
         sg.Input(key=('-SPECIFICATION TITLE-', lvl_1)),
         sg.Text ('Select IFC Version:')],
        [sg.Frame('Applicability', sub_frame, key=f'-APPLICABILITY {lvl_1}-', relief = 'sunken')],
        [sg.Column(layout_requirement_frame(lvl_1,lvl_2),key = f'-SPEC REQUIREMENT {lvl_1}-')],
        [sg.pin(sg.Column(column_layout))]],
    layout = [[sg.Frame(f'Specification N° {lvl_1}', frame_layout, key=('-FRAME LVL 1-',lvl_1), relief='groove')]]
    return layout

def layout_requirement_frame(lvl_1,lvl_2):
    frame_layout = [
        [sg.Text ('Should have a  '),
         sg.Text ('With')],
        [sg.Column(layout_parameter_req(lvl_1,lvl_2),key=f'-REQ FACET PARAMETERS {lvl_1, lvl_2}-')],
    ]
    layout = [[sg.pin(sg.Frame(f'Requirement {lvl_2}', frame_layout, key=f'-REQUIREMENT {lvl_1,lvl_2}-', relief = 'sunken'))]]
    return layout

def layout_parameter_req(lvl_1,lvl_2):
    items  = []
    frame_layout = [
        [sg.Text(item, size=(15, 1)),
         sg.Input(key=('req', item, lvl_1, lvl_2)),
         sg.Text('Required'), sg.Push(), sg.Button('+')]
            for item in items
    ]
    layout = [[sg.pin(sg.Frame('', frame_layout, key=f'- FRAME REQ{lvl_1,lvl_2}-', relief='flat'))]]
    return layout

lvl_1, lvl_2 = 1, 1
layout = layout_specification_frame(lvl_1,lvl_2)
window = sg.Window("Window Title", layout)

while True:

    event, values = window.read()

    if event == sg.WIN_CLOSED:
        break

    elif event[0] == '-ADD REQ-' :
        lvl_2 += 1
        if f'-REQUIREMENT {lvl_1,lvl_2}-' in window.AllKeysDict:
            window[f'-REQUIREMENT {lvl_1,lvl_2}-'].update(visible=True)
        else :
            window.extend_layout(window[f'-SPEC REQUIREMENT {lvl_1}-'],layout_requirement_frame(lvl_1,lvl_2))

    elif event[0] == '-REMOVE REQ-' :
        if lvl_2 > 1:
            window[f'-REQUIREMENT {lvl_1,lvl_2}-'].update(visible=False)
            lvl_2 -= 1

window.close()