Describe the bug
When running pickFiles() or saveFile(), the dialog to choose the file appears behind my program in Linux.

Platform

• Android
• iOS
• Web
• Desktop

Platform OS version
Ubuntu 24.04.2 LTS

How are you picking?

await FilePicker.platform.pickFiles(
      fileName: 'test',
      type: FileType.custom,
      allowedExtensions: ['txt'],
      bytes: utf8.encode('abc'),
      lockParentWindow: true,
    );

Details to reproduce the issue
Run pickFiles in any Flutter project.

Error Log
N/A

Screenshots and/or video
N/A

Flutter Version details
[✓] Flutter (Channel stable, 3.35.4, on Ubuntu 24.04.2 LTS 6.8.0-85-generic, locale en_US.UTF-8) [93ms]
• Flutter version 3.35.4 on channel stable at /usr/bin/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision d693b4b9db (3 weeks ago), 2025-09-16 14:27:41 +0000
• Engine revision c298091351
• Dart version 3.9.2
• DevTools version 2.48.0
• Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, enable-lldb-debugging

[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0) [2.7s]
• Android SDK at /home/michele/Android/Sdk
• Emulator version 35.6.11.0 (build_id 13610412) (CL:N/A)
• Platform android-36, build-tools 36.0.0
• Java binary at: /snap/android-studio/209/jbr/bin/java
This is the JDK bundled with the latest Android Studio installation on this machine.
To manually set the JDK path, use: flutter config --jdk-dir="path/to/jdk".
• Java version OpenJDK Runtime Environment (build 21.0.7+-13880790-b1038.58)
• All Android licenses accepted.

[✓] Chrome - develop for the web [30ms]
• Chrome at google-chrome

[✓] Linux toolchain - develop for Linux desktop [2.4s]
• Ubuntu clang version 18.1.3 (1ubuntu1)
• cmake version 4.1.2
• ninja version 1.11.1
• pkg-config version 1.8.1
• OpenGL core renderer: Mesa Intel(R) UHD Graphics 630 (CFL GT2) (X11)
• OpenGL core version: 4.6 (Core Profile) Mesa 24.2.8-1ubuntu124.04.1 (X11)
• OpenGL core shading language version: 4.60 (X11)
• OpenGL ES renderer: Mesa Intel(R) UHD Graphics 630 (CFL GT2) (X11)
• OpenGL ES version: OpenGL ES 3.2 Mesa 24.2.8-1ubuntu124.04.1 (X11)
• OpenGL ES shading language version: OpenGL ES GLSL ES 3.20 (X11)
• GL_EXT_framebuffer_blit: yes (X11)
• GL_EXT_texture_format_BGRA8888: yes (X11)

[✓] Android Studio (version 2025.1.3) [25ms]
• Android Studio at /snap/android-studio/209
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 21.0.7+-13880790-b1038.58)

[✓] Android Studio (version 2025.1.2) [17ms]
• Android Studio at /snap/android-studio/205
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 21.0.6+-13391695-b895.109)

[✓] Connected device (2 available) [497ms]
• Linux (desktop) • linux • linux-x64 • Ubuntu 24.04.2 LTS 6.8.0-85-generic
• Chrome (web) • chrome • web-javascript • Google Chrome 138.0.7204.100

[✓] Network resources [662ms]
• All expected network resources are available.

• No issues found!

Additional context
N/A.