Column scroll distance not updated until window is manually resized

Start with the provided reproduction using FreeSimpleGUI 5.1.1 on macOS, focusing on the scrollable Column keyed as LAYOUT_COLUMN and its contents_changed() call after TEST1SEC visibility changes. Trace the Column scroll handling and verify that expanding and collapsing sections updates the scrollbars without manually resizing the window.

I'm having trouble with using tabs or the "visible" property of frames within a column that has scrolling enabled.

I'm trying to create a layout that fits vertically on the screen when the app is started, so I made some of the frames invisible, and allow them to be made visible when needed. I've tried tabs and the "visible" property, but the scrollbars of the containing column are not updating correctly.

If the frames are hidden to begin with, the main column scrollbars are set for the minimized content, and they don't update when the content is maximized. If the frames are visible to begin with, the scrollbars are set correctly - but when the frames are minimized they reset to the smaller size, and when the frames are maximized, they don't update again.

For some reason, the scrollbars reset when minimizing sections, but not when maximizing sections.

If you maximize sections and then manually resize the window by any amount, the scrollbars will reset to the current view. But this does not happen when programmatically resizing the window, so it's not a workaround.

import FreeSimpleGUI as sg

def collapse(title, layout, key):
    """
    Helper function that creates a Column that can be later made hidden, thus appearing "collapsed"
    :param layout: The layout for the section
    :param key: Key used to make this seciton visible / invisible
    :return: A pinned column that can be placed directly into your layout
    :rtype: sg.pin
    """
    # return sg.pin(sg.Column(layout, key=key))
    return sg.pin(sg.Frame(title, layout, border_width=6,
        relief="ridge", expand_x=True, visible=False, key=key))

test_1_multiline = [
   [sg.Sizer(h_pixels=3),
    sg.Multiline(size=(83, 13),
    font=('Courier', 14, 'bold'), background_color='#fdfdfc',
    expand_x=True, disabled=True,
    no_scrollbar=True, key='TEST_1_MLINE'),
    sg.Sizer(h_pixels=3)],
   [sg.Sizer(h_pixels=0, v_pixels=5)]
]

test_1_col1 = [
   [sg.Frame('Test Frame 1',
    test_1_multiline, expand_x=True, border_width=1, relief='ridge',
    font=('Helvetica', 13, 'bold'), title_location=sg.TITLE_LOCATION_TOP)]
]

test_1_col2 = [
   [sg.Text('Test text 1')]
]

test_1_layout = [
   [sg.Column(test_1_col1, element_justification='centered',
    expand_x=True)],
   [sg.Column(test_1_col2, expand_x=True)]
]

sec1 = sg.Column(
         [
            [sg.T(sg.SYMBOL_RIGHT, enable_events=True, k='OPEN_TEST1SEC'),
             sg.T('Binary Operations', enable_events=True,
                  font=(None, 14,"bold"), k='OPEN_TEST1SEC_TEXT')],
            [collapse('', test_1_layout, 'TEST1SEC'), sg.Sizer(h_pixels=5)]
         ],
         key='SEC1_KEY'
      )

# App Control Button Frame
sec5 = sg.Frame("",
   [
      [
         sg.Column(
            [
               [
                  sg.Button('Example', font='Helvetica 11', key='-EXAMPLE-'),
                  sg.Button('Clear', font='Helvetica 11', key='-CLEAR-'),
                  sg.Text('', text_color='red', font='None 14 bold',
                          key='-BTN_MESSAGES-'),
                  sg.Push(),
                  sg.Button('About', font=('Helvetica', 12)),
                  sg.Button(' Exit ', font=('Helvetica', 12, 'bold'))
               ]
            ],
            expand_x=True,
         )
      ]
   ],
   expand_x=True,
   border_width=6,
   relief="ridge",
)

page_layout = [
      [sec1],
      # [sec2],
      # [sec3],
      # [sec4],
      [sg.Sizer(h_pixels=5), sec5, sg.Sizer(h_pixels=10)],
      [sg.Sizer(v_pixels=8)]
]

layout = [
            # [results_frame],
            [sg.Column(page_layout,
               expand_x=True,
               expand_y=True,
               scrollable=True,
               # vertical_scroll_only=True,
               key='LAYOUT_COLUMN'),
            ]
         ]

# window = sg.Window('IP MAP Calculator', layout, size=(796, 500), 
# window = sg.Window('IP MAP Calculator', layout, size=(771, 200), 
window = sg.Window('IP MAP Calculator', layout, size=(700, 200), 
            resizable=True, enable_close_attempted_event=True,
            finalize=True,
            location=sg.user_settings_get_entry('-location-', (None, None))) # resizable=True, # size=(777, 1000)

# Main Event Loop
# opened1, opened2, opened3 = False, False, False
opened1 = False
count = 0

while True:
   event, values = window.read()
   print(event, values)

   if event in (' Exit ', sg.WINDOW_CLOSE_ATTEMPTED_EVENT):
      # Save screen location when closing window
      sg.user_settings_set_entry('-location-', window.current_location())
      break

   if event.startswith('OPEN_TEST1SEC'):
      opened1 = not opened1
      window['OPEN_TEST1SEC'].update(sg.SYMBOL_DOWN if opened1 else sg.SYMBOL_RIGHT)
      window['TEST1SEC'].update(visible=opened1)
      window['LAYOUT_COLUMN'].contents_changed() # per Controls > Column > scrollable - Description
      # a, b = window.size
      # window.size = (700, b + 1)
      # print(window.size)
      # window.refresh()

# print(window.size) # on any event

window.close()

https://github.com/user-attachments/assets/a249df42-f295-44c8-87d0-81f1b775a8a7

macOS Sonoma 14.7
Python 3.12.4
FSG Version: 5.1.1
tkinter version 8.6