<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto">I am using onGenerateRoute to perform navigation.  My onGenerateRoute method creates MaterialPageRoute objects with <code class="notranslate">maintainState: false</code>.  When navigating backwards, TextField widgets can no longer be focused and edited.  <a href="https://gist.github.com/tlarsen7572/fdd91e2818c89430f87785371cb96f6a">This Gist</a> produces the issue.  When the home page first loads, its TextField can be edited.  When you navigate to Next and then go back, the TextField can no longer be edited.</p>
<h2 dir="auto">Flutter Doctor</h2>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="✓] Flutter (on Mac OS X 10.13.3 17D47, locale en-US, channel master)
    • Flutter version 0.1.3-pre.46 at /Users/tlarsen/flutter
    • Framework revision f914e701c5 (4 days ago), 2018-02-19 21:12:17 +0000
    • Engine revision 13cf22c284
    • Dart version 2.0.0-dev.27.0-flutter-0d5cf900b0

[✓] Android toolchain - develop for Android devices (Android SDK 26.0.2)
    • Android SDK at /Users/tlarsen/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-26, build-tools 26.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 9.2, Build version 9C40b
    • ios-deploy 1.9.2
    • CocoaPods version 1.3.1

[✓] Android Studio (version 3.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] IntelliJ IDEA Community Edition (version 2017.3.4)
    • Flutter plugin version 21.2.3
    • Dart plugin version 173.4548.30

[✓] Connected devices
    • iPhone 7 • B3ECB1A2-524B-4C57-801A-C34AE83D617E • ios • iOS 11.2 (simulator)

• No issues found!"><pre class="notranslate"><code class="notranslate">✓] Flutter (on Mac OS X 10.13.3 17D47, locale en-US, channel master)
    • Flutter version 0.1.3-pre.46 at /Users/tlarsen/flutter
    • Framework revision f914e701c5 (4 days ago), 2018-02-19 21:12:17 +0000
    • Engine revision 13cf22c284
    • Dart version 2.0.0-dev.27.0-flutter-0d5cf900b0

[✓] Android toolchain - develop for Android devices (Android SDK 26.0.2)
    • Android SDK at /Users/tlarsen/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-26, build-tools 26.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 9.2, Build version 9C40b
    • ios-deploy 1.9.2
    • CocoaPods version 1.3.1

[✓] Android Studio (version 3.0)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] IntelliJ IDEA Community Edition (version 2017.3.4)
    • Flutter plugin version 21.2.3
    • Dart plugin version 173.4548.30

[✓] Connected devices
    • iPhone 7 • B3ECB1A2-524B-4C57-801A-C34AE83D617E • ios • iOS 11.2 (simulator)

• No issues found!
</code></pre></div>
<h2 dir="auto">Steps to Reproduce</h2>

<ol dir="auto">
<li>Navigate to search screen.</li>
<li>Enter search term and tap on a result.</li>
<li>Navigate away from search screen.</li>
<li>Return to search screen using the back button.</li>
<li>Search text field becomes unresponsive.</li>
</ol>
<p dir="auto">Reproduced here: <a href="https://gist.github.com/JordanADavies/c7b630681aa81940d254876078a2f7a0">https://gist.github.com/JordanADavies/c7b630681aa81940d254876078a2f7a0</a></p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="flutter doctor -v
[✓] Flutter (Channel beta, v0.9.4, on Mac OS X 10.14.1 18B75, locale en-GB)
    • Flutter version 0.9.4 at /Users/jordandavies/Documents/development/flutter
    • Framework revision f37c235c32 (5 weeks ago), 2018-09-25 17:45:40 -0400
    • Engine revision 74625aed32
    • Dart version 2.1.0-dev.5.0.flutter-a2eb050044

[✓] Android toolchain - develop for Android devices (Android SDK 28.0.3)
    • Android SDK at /Users/jordandavies/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)
    • All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 10.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 10.1, Build version 10B61
    • ios-deploy 2.0.0
    • CocoaPods version 1.5.3

[✓] Android Studio (version 3.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 29.1.1
    • Dart plugin version 181.5656
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)

[✓] Connected devices (1 available)
    • iPhone XR • 4018CC7F-D913-4181-8CF3-C29A87529EA2 • ios • iOS 12.1 (simulator)

• No issues found!"><pre class="notranslate"><code class="notranslate">flutter doctor -v
[✓] Flutter (Channel beta, v0.9.4, on Mac OS X 10.14.1 18B75, locale en-GB)
    • Flutter version 0.9.4 at /Users/jordandavies/Documents/development/flutter
    • Framework revision f37c235c32 (5 weeks ago), 2018-09-25 17:45:40 -0400
    • Engine revision 74625aed32
    • Dart version 2.1.0-dev.5.0.flutter-a2eb050044

[✓] Android toolchain - develop for Android devices (Android SDK 28.0.3)
    • Android SDK at /Users/jordandavies/Library/Android/sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-28, build-tools 28.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)
    • All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 10.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 10.1, Build version 10B61
    • ios-deploy 2.0.0
    • CocoaPods version 1.5.3

[✓] Android Studio (version 3.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 29.1.1
    • Dart plugin version 181.5656
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)

[✓] Connected devices (1 available)
    • iPhone XR • 4018CC7F-D913-4181-8CF3-C29A87529EA2 • ios • iOS 12.1 (simulator)

• No issues found!
</code></pre></div>