bug: Monitor power cycling (flickering) on dual-monitor setup with flet-desktop 0.80.2

[FeodorFitsner]

Duplicate Check

• I have searched the opened issues and there are no duplicates

Describe the bug

Describe the bug Running a Flet script using flet-desktop==0.80.2 causes my monitors to repeatedly turn off and on (power cycling). This issue specifically occurs on this version and is resolved by downgrading to a previous version.

Environment

OS: Windows (or mention your OS)

Flet Version: 0.80.2 (Problematic) / 0.28.3 (Working)

Hardware: Dual Monitor Setup (Samsung Odyssey)

Python Version: (e.g., 3.12.x)

To Reproduce

Create a virtual environment with flet==0.80.2 and flet-desktop==0.80.2.

Run any basic Flet desktop script (even a simple "Hello World").

Observe the monitors turning off and on immediately.

Observed Behavior When the script is executed in the venv with version 0.80.2, both monitors (Samsung Odyssey) keep turning off and on. I spent a full day troubleshooting this and confirmed it is a version-specific regression.

Expected Behavior The Flet window should open normally without affecting the monitor's power state or display stability.

Additional Context

I have two virtual environments:

Env A: Flet 0.28.3 (Works perfectly)

Env B: Flet 0.80.2 (Causes the bug)

The issue is definitely narrowed down to flet-desktop==0.80.2. Downgrading specifically this package to 0.28.3 fixes the issue immediately.

I'm a big fan of Flutter and Flet. Hope this helps in improving the framework!

Code sample

Code

[Paste your code here]

To reproduce

1. install python ver 3.12.8
2. uv init
3. uv pip install flet (automatically installed 0.80.2)
4. just import flet and just add one iconbutton
5. test run

Expected behavior

No response

Screenshots / Videos

Captures

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Operating System

Windows

Operating system details

windows

Flet version

0.80.2

Regression

Yes, it used to work in a previous Flet version (please specify the version in additional details)

Suggestions

No response

Logs

Logs

[Paste your logs here]

Additional details

No response

[tedthebot]

Thanks for the detailed report — that sounds severe and definitely worth investigating.

To help narrow this down, could you share:

• Exact Windows version/build (winver), GPU model(s), and driver version(s).
• Monitor details: resolution, refresh rate, connection type (HDMI/DP), and whether HDR/VRR/G‑Sync/FreeSync is enabled.
• Whether the flicker happens with a minimal app like:

import flet as ft

ft.app(target=lambda page: page.add(ft.IconButton(icon=ft.icons.ADD)))

• Whether it occurs in windowed vs. maximized/fullscreen.
• Any console output (flet run logs), even if it looks empty.

Workaround-wise, you’ve already confirmed downgrading flet-desktop to 0.28.3 fixes it — thank you. If you can also test 0.80.1 vs 0.80.2, that would help pinpoint the regression window.

If you can attach a short video capture, that would be great too (blur/redact any sensitive info).

[FeodorFitsner]

A simple app causes flickering, yes.