Repository: flutter
Issue: [Windows, IME] Sogou input dropdown is mispositioned after committing
Labels: a: text input,engine,a: fidelity,platform-windows,a: desktop,a: annoyance,from: china,P2,team-windows,triaged-windows

![动画](https://user-images.githubusercontent.com/5417624/137240080-e1dfcc32-b5cc-48c2-a1cc-60603c576970.gif)

App: Any apps with 2 text fields

Reproducing steps:

1. Must use Sogou Chinese input. Not all IME triggers (such as Windows Japanese IME.)
2. Type a few words in a text field and commit. (Canceling doesn't trigger.)
3. Focus the other text field and type.

Expected: The candidate dropdown is positioned correctly.

Actual: The candidate dropdown is positioned in the previous textfield.

Version (latest master):
<details><pre>
[√] Flutter (Channel master, 2.6.0-12.0.pre.381, on Microsoft Windows [Version 10.0.19043.1288], locale en-US)
    • Flutter version 2.6.0-12.0.pre.381 at C:\Users\DKWings\src\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision ef634b39a5 (2 hours ago), 2021-10-18 15:10:33 -0700
    • Engine revision faa45f497f
    • Dart version 2.15.0 (build 2.15.0-226.0.dev)

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at D:\AndroidSdk
    • Platform android-30, build-tools 30.0.3
    • Java binary at: D:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
    • All Android licenses accepted.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop for Windows (Visual Studio Community 2019 16.8.3)
    • Visual Studio at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community
    • Visual Studio Community 2019 version 16.8.30804.86
    • Windows 10 SDK version 10.0.19041.0

[√] Android Studio (version 4.0)
    • Android Studio at D:\Program Files\Android\Android Studio
    • 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 1.8.0_242-release-1644-b01)

[√] IntelliJ IDEA Community Edition (version 2020.1)
    • IntelliJ at D:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.1.4
    • 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

[√] VS Code, 64-bit edition (version 1.58.0)
    • VS Code at C:\Program Files\Microsoft VS Code
    • Flutter extension version 3.25.0

[√] Connected device (3 available)
    • Windows (desktop) • windows • windows-x64    • Microsoft Windows [Version 10.0.19043.1288]
    • Chrome (web)      • chrome  • web-javascript • Google Chrome 94.0.4606.81
    • Edge (web)        • edge    • web-javascript • Microsoft Edge 93.0.961.52

• No issues found!
</pre></details>

Originally filed at https://github.com/flutter/flutter/issues/90503#issuecomment-942888715.