anchor.diff:        valueListenable: serviceManager.connectedState,
         builder: (context, connectedState, child) {
           if (connectedState.connected) {
  -          final app = serviceManager.connectedApp;
  +          final app = serviceManager.connectedApp!;
   
             String description;
  -          if (!app.isRunningOnDartVM) {
  +          if (!app.isRunningOnDartVM!) {
               description = 'web app';
             } else {
  -            final VM vm = serviceManager.vm;
  +            final VM vm = serviceManager.vm!;
               description =
                   '${vm.targetCPU}-${vm.architectureBits} ${vm.operatingSystem}';
             }
   
  -          final color = Theme.of(context).textTheme.bodyText2.color;
  +          final color = Theme.of(context).textTheme.bodyText2!.color;
   
             return Row(
               mainAxisAlignment: MainAxisAlignment.end,
               children: [
                 ValueListenableBuilder(
                   valueListenable: serviceManager.deviceBusy,
  -                builder: (context, isBusy, _) {
  +                builder: (context, bool isBusy, _) {
                     return SizedBox(
                       width: smallProgressSize,
                       height: smallProgressSize,
                       child: isBusy
                           ? SmallCircularProgressIndicator(
  -                            valueColor: AlwaysStoppedAnimation<Color>(color),
  +                            valueColor: AlwaysStoppedAnimation<Color?>(color),
                             )
                           : const SizedBox(),
                     );
  
positive.code: 
      children.add(const BulletSpacer());
  
      // Optionally display an isolate selector.
      if (currentScreen != null) {
        children.add(
          ValueListenableBuilder<bool>(
            valueListenable: currentScreen.showIsolateSelector,
            builder: (context, showIsolateSelector, _) {
              return showIsolateSelector
                  ? Flexible(
                      child: Row(
                        children: const [
                          Expanded(
                            child: Center(
                              child: IsolateSelector(),
                            ),
                          ),
                          BulletSpacer(),
                        ],
                      ),
                    )
                  : Container();
            },
          ),
        );
      }
  
      // Optionally display page specific status.
      if (currentScreen != null) {
        final Widget pageStatus =
            buildPageStatus(context, currentScreen, textTheme);
  
        if (pageStatus != null) {
          children.add(Expanded(
            child: Align(
              child: buildPageStatus(context, currentScreen, textTheme),
            ),
          ));
  
          children.add(const BulletSpacer());
        }
      }
  
      // Always display connection status (docked to the right).
  
negative.code:                     value: ref,
                      child: Row(
                        children: [
                          ref.isSystemIsolate ?? false
                              ? const Icon(Icons.settings_applications)
                              : const Icon(Icons.call_split),
                          const SizedBox(width: denseSpacing),
  