Can't scroll TextArea using FormattedTextControl for ANSI colors

# Repro case for prompt_toolkit issue with FormattedTextControl and scrolling in TextArea

from prompt_toolkit import Application
from prompt_toolkit.layout import Layout, HSplit, VSplit
from prompt_toolkit.widgets import TextArea
from prompt_toolkit.layout.controls import FormattedTextControl
from prompt_toolkit import ANSI
from prompt_toolkit.key_binding import KeyBindings

def create_repro_app():
    # Create a TextArea with regular text
    regular_text_area = TextArea(
        text="Regular TextArea:\n" + "\n".join([f"Line {i}" for i in range(100)]),
        scrollbar=True,
        wrap_lines=True,
    )

    # Create a TextArea with FormattedTextControl for ANSI text
    ansi_text = ANSI("\n".join([
        f"\033[1;3{i%8}mANSI Formatted Line {i}\033[0m" for i in range(100)
    ]))
    formatted_text_area = TextArea(
        scrollbar=True,
        wrap_lines=True,
    )
    formatted_text_area.window.content = FormattedTextControl(ansi_text)

    # Create the layout
    layout = Layout(
        HSplit([
            VSplit([
                regular_text_area,
                formatted_text_area,
            ]),
        ])
    )

    # Create key bindings
    kb = KeyBindings()

    @kb.add('tab')
    def _(event):
        # Toggle focus between text areas
        if event.app.layout.has_focus(regular_text_area):
            event.app.layout.focus(formatted_text_area)
        else:
            event.app.layout.focus(regular_text_area)

    @kb.add('escape', 'q')
    def _(event):
        """Quit the application when 'escape' followed by 'q' is pressed."""
        event.app.exit()


    # Create and return the application
    return Application(layout=layout, key_bindings=kb, full_screen=True)

def run_repro():
    app = create_repro_app()
    app.run()

# Run the repro case
run_repro()

# Note: This repro case demonstrates that while the regular TextArea
# scrolls normally, the TextArea with FormattedTextControl for ANSI
# text does not scroll properly for multiline content.
# Use Tab key to switch focus between the two text areas.

Start by running the provided reproduction and compare scrolling in the regular TextArea with the TextArea whose window content is a FormattedTextControl containing ANSI text. Trace the TextArea, window, and FormattedTextControl scrolling behavior; done means multiline ANSI content scrolls normally like the regular TextArea.