anchor.diff:      return Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
  -        if (hasCopyButton)
  -          Padding(
  -            padding: isDesktop
  -                ? EdgeInsets.only(bottom: 8)
  -                : EdgeInsets.symmetric(vertical: 8),
  -            child: FlatButton(
  -              color: Colors.white.withOpacity(0.15),
  -              materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
  -              padding: EdgeInsets.symmetric(horizontal: 8),
  -              shape: RoundedRectangleBorder(
  -                borderRadius: BorderRadius.all(Radius.circular(4)),
  -              ),
  -              onPressed: () async {
  -                await Clipboard.setData(ClipboardData(text: _plainTextCode))
  -                    .then(_showSnackBarOnCopySuccess)
  -                    .catchError(_showSnackBarOnCopyFailure);
  -              },
  -              child: Text(
  -                GalleryLocalizations.of(context).demoCodeViewerCopyAll,
  -                style: Theme.of(context).textTheme.button.copyWith(
  -                      color: Colors.white,
  -                      fontWeight: FontWeight.w500,
  -                    ),
  -              ),
  -            ),
  -          ),
  +        Padding(
  +          padding: isDesktop
  +              ? EdgeInsets.only(bottom: 8)
  +              : EdgeInsets.symmetric(vertical: 8),
  +          child: FlatButton(
  +            color: Colors.white.withOpacity(0.15),
  +            materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
  +            padding: EdgeInsets.symmetric(horizontal: 8),
  +            shape: RoundedRectangleBorder(
  +              borderRadius: BorderRadius.all(Radius.circular(4)),
  +            ),
  +            onPressed: () async {
  +              // The future will not complete on web, thus no
  +              // Snackbar will be shown, see https://github.com/flutter/flutter/issues/49349.
  +              await Clipboard.setData(ClipboardData(text: _plainTextCode))
  +                  .then(_showSnackBarOnCopySuccess)
  +                  .catchError(_showSnackBarOnCopyFailure);
  +            },
  +            child: Text(
  +              GalleryLocalizations.of(context).demoCodeViewerCopyAll,
  +              style: Theme.of(context).textTheme.button.copyWith(
  +                    color: Colors.white,
  +                    fontWeight: FontWeight.w500,
  +                  ),
  +            ),
  +          ),
  +        ),
           Expanded(
             child: SingleChildScrollView(
               child: Container(
  
positive.code: }
  
  class CodeDisplayPage extends StatelessWidget {
    const CodeDisplayPage(this.code, {this.hasCopyButton = true});
  
    final CodeDisplayer code;
    final bool hasCopyButton;
  
    Widget build(BuildContext context) {
      final isDesktop = isDisplayDesktop(context);
  
negative.code:             maxHeight: maxSectionHeight,
              codeWidget: CodeDisplayPage(
                _currentConfig.code,
              ),
            ),
          );
  