UI Flickering/Shaking on Window Resize (macOS)

[elgar328]

Description:

When resizing the application window for the to_do_mvc and slider_demo examples, the internal UI elements exhibit severe flickering and shaking, making the resizing experience visually disruptive.

Dec-08-2025.11-31-01.mp4

Dec-08-2025.11-29-16.mp4

Reproduction Steps:

1. Run either cargo run --example to_do_mvc or cargo run --example slider_demo.
2. Resize the application window by dragging an edge or corner.
3. Observe the severe UI flickering/shaking.

Expected Behavior:

When resizing the window, the UI elements should smoothly adjust their layout and size without any visual artifacts such as flickering or shaking.

Observed Behavior:

UI elements within the application window appear to flicker, jump, or shake erratically during the resizing operation. The visual instability persists as long as the window is being resized.

Environment:

• Operating System: macOS Sequoia 15.6.1
• Hardware: Apple M4 Max
• Rust Version: rustc 1.89.0 (29483883e 2025-08-04)

Additional Context:

I have observed similar flickering/shaking behavior during window resizing in other Rust GUI libraries like egui and slint when tested on the same macOS environment. However, this particular issue was not present when testing applications built with dioxus on the same machine.

[PoignardAzur]

If egui and slint have the same issue, then it might be a winit bug?

[elgar328]

If egui and slint have the same issue, then it might be a winit bug?

I suspect this issue might be related to macOS HiDPI (Retina) scaling, specifically regarding the scale factor or the handling of logical vs. physical pixels.

[noelgbl]

Might be related to this issue in egui