Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

35.2.1

What operating system(s) are you using?

Windows

Operating System Version

Windows 11 24H2

What arch are you using?

x64

Last Known Working Electron version

No response

Expected Behavior

• The material effect (Acrylic/Mica) should persist in all maximize/restore scenarios.
• Rounded corners should remain consistent.
• Windows 11 should ideally support the all materials for better native integration.

Actual Behavior

Issue Description

As mentioned in issues #42393 and #41824, previous versions of Electron experienced a bug where the backgroundMaterial effect (e.g., Acrylic/Mica) would disappear after maximizing a frameless window.

While the issue has been partially fixed for cases involving win.maximize() and win.restore(), the material effect still fails under other conditions.

Reproduction Cases

The behavior varies depending on how the window is maximized/restored:

1. ✅ Works Correctly
   • Clicking the maximize/restore buttons (win.maximize() / win.restore()) retains the material effect.

2. ❌ Drag to Maximize → Drag to Restore
   • Dragging the window to the top (maximize) and then dragging it down (restore) causes:
     • Material effect lost (incorrect background color)
     • Rounded corners remain intact

3. ❌ Double-Click to Maximize → Double-Click to Restore
   • Double-clicking the title bar to maximize and restore results in:
     • Material effect lost (incorrect background color)
     • Rounded corners remain intact

4. ❌ Click Maximize Button → Drag to Restore
   • Clicking the maximize button (works correctly), then dragging to restore causes:
     • Material effect lost
     • Rounded corners also lost

5. ⚠️ Click Maximize Button → Double-Click to Restore
   • Clicking the maximize button (works correctly), then double-clicking to restore:
     • Material effect remains
     • Rounded corners lost

Code Example

win = new BrowserWindow({
    frame: false,
    width: 1200,
    height: 640,
    minWidth: 800,
    minHeight: 500,
    backgroundMaterial: "acrylic", // Should also support "mica" for Win11
    webPreferences: {
        enableRemoteModule: true,
        enableSmoothScrolling: true,
        webSecurity: false,
        devTools: true
    }
});

📊 Behavior Summary Table

Testcase Gist URL

No response

Additional Information

No response