Flet windows don't open centered by default, which is quite annoying

[chenyyoung]

Hey, could the default Flet window appear centered on the screen at startup instead of in the top-left corner? When using page.window.center(), I notice the window flickers from the top-left to the center during launch, which isn't a smooth experience

[ndonkoHenri]

Can you please try the latest pre-release and let know if you still see an issue?

[chenyyoung]

I installed Flet version 0.70 in a UV virtual environment. After launching the program, the window does not center automatically—adding page.window.center() doesn’t help either. In version 0.28.3, that same line of code would correctly center the window, even though the transition from the top‑left corner to the center wasn’t perfectly smooth. Unfortunately, version 0.70 doesn’t seem to natively support window centering, and it still has a few bugs… Still, I love Flet and truly wish it all the best.

[RezaErfani67]

i'm testing with version 0.8.0 and bug stil exist.

 page.window.center()

[ndonkoHenri]

You need to use await page.window.center(), as mentioned in your terminal.

[oktl]

If you haven't figured it out yet this works for me. Make your main async and then after everything is loaded await page.window.center.
Works on macOS, haven't tried Windows or Linux.

async def main(page: ft.Page) -> None:
    """Initialize and configure the main application page.

    Sets up window dimensions, theme, padding, and initializes the application
    state and UI components. Attaches event handlers and centers the window.

    Args:
        page: The Flet page object representing the application window.
    """
    try:
        # Set up logging first thing.
        setup_logging()
        logger.info("Starting application")

        # Configure page-level settings including window size, colors, and title.
        page.title = "Flet test"
        page.window.width = 750
        page.window.height = 1360
        page.padding = 30

        settings = load_settings()
        state = AppState(settings=settings)
        page.theme_mode = (
            ft.ThemeMode.DARK if state.is_dark_mode else ft.ThemeMode.LIGHT
        )
        controls = build_main_view(page, state)
        page.add(controls)

        attach_handlers(page, state)

        await page.window.center()

    except Exception as e:
        logger.error(f"Application error: {e}")
        logger.exception("Full traceback:")
        raise


def run() -> None:
    ft.run(main, assets_dir="assets")


if __name__ == "__main__":
    run()

[ndonkoHenri]

In the latest versions, use await page.window.center(), with your main function being async.
If you need to hide the window before doing this, see this example.

[hitzsf]

I'm running Flet 0.82 on Windows 10, and with the example ，the window flashes in the corner momentarily during startup.

[ndonkoHenri]

Can you please share a screen recording of you running the code and then the app's behavior?

Feel free to do it here or in a new bug issue.

[chenyyoung]

Can you please share a screen recording of you running the code and then the app's behavior?

Feel free to do it here or in a new bug issue.

basic-flet-component-launch.mp4

example-code-launch.mp4

Here are two screen recordings. In one of them, it can be observed that when launching the sample code for version 0.82.2, the window still moves quickly from the top-left corner of the screen to the center, which looks like a flicker. From the other screen recording, it is evident that the Flet basic component appears in the top-left corner of the screen upon launch. I believe this is the root cause of the "flicker-to-center" phenomenon. Therefore, is it possible to directly make the Flet basic component launch in the center of the screen instead of the top-left corner?

[hitzsf]

根本就没有办法解决这个问题，sleep 是个笑话 At 2026-03-16 14:53:17, "chenyyoung" ***@***.***> wrote: Can you please share a screen recording of you running the code and then the app's behavior? Feel free to do it here or in a new bug issue. https://github.com/user-attachments/assets/3a469e3c-a5be-46f0-914f-3bd1698f8229 https://github.com/user-attachments/assets/b54e3fbb-2640-4898-9ba9-45e1b7e6293f Here are two screen recordings. In one of them, it can be observed that when launching the sample code for version 0.82.2, the window still moves quickly from the top-left corner of the screen to the center, which looks like a flicker. From the other screen recording, it is evident that the Flet basic component appears in the top-left corner of the screen upon launch. I believe this is the root cause of the "flicker-to-center" phenomenon. Therefore, is it possible to directly make the Flet basic component launch in the center of the screen instead of the top-left corner? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you commented.Message ID: ***@***.***>