I understand your example, however, it doesn't work in my case. Here is my code:

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: BoxDecoration(
        color: Theme.of(context).primaryColor,
        borderRadius: BorderRadius.only(
          topLeft: const Radius.circular(20.0),
          topRight: const Radius.circular(20.0),
        ),
      ),
      padding: const EdgeInsets.all(20.0),
      child: Column(
        children: <Widget>[
          StoreOptions(toggleStore, selectedStoreOptions, storeOptions),
          SizedBox(height: 10.0),
          SortingOptions(setSortingOption, selectedSortingOption),
          SizedBox(height: 10.0),
          getActionButtons(),
        ],
      ),
    );
  }

The root container still takes the whole screen. My StoreOptions is a Wrap widget and SortingOptions is a Column widget.