A BaseGridFragment contains a VerticalGridSupportFragment which is modified to allow focus to escape it.

BaseGridFragment.kt

abstract class BaseGridFragment : Fragment() {

    private var lifecycleCallbacks: FragmentManager.FragmentLifecycleCallbacks? = null

    /**
     * If your fragment contains a VerticalGridSupportFragment, it automatically includes a search button you can disable.
     * However, the focus search listener is not disabled, and it does conflict with our implementation for showing the menu.
     * Don't forget to save a reference to the callbacks to unsubscribe when destroying the fragment.
     */
    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        lifecycleCallbacks = object : FragmentManager.FragmentLifecycleCallbacks() {
            override fun onFragmentStarted(fm: FragmentManager?, f: Fragment?) {
                if (f is VerticalGridSupportFragment) {
                    val browseFrameLayout = f.getView()!!.findViewById<View>(
                            android.support.v17.leanback.R.id.grid_frame) as BrowseFrameLayout
                    browseFrameLayout.onFocusSearchListener = null
                }
            }
        }
        childFragmentManager.registerFragmentLifecycleCallbacks(lifecycleCallbacks, true)
    }

    override fun onDestroyView() {
        childFragmentManager.unregisterFragmentLifecycleCallbacks(lifecycleCallbacks)
        super.onDestroyView()
    }
}