title: BottomSheetBehavior inside nested fragment not working
body: <p>My goal is to hide toolbar on scroll up and show on down while tabLayout does not hides but moves up while toolbar hidden.
  I have main activity with FrameLayout that handles fragments</p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:id="@+id/main_cord"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"&gt;
  
  &lt;android.support.design.widget.AppBarLayout
      android:id="@+id/toolbar_supervisor"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      app:elevation="0dp"&gt;
      &lt;android.support.v7.widget.Toolbar
          android:id="@+id/toolbar"
          android:layout_width="match_parent"
          android:layout_height="?attr/actionBarSize"
          app:layout_scrollFlags="scroll|enterAlways"&gt;
          &lt;TextView
              android:id="@+id/toolbar_title"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:gravity="center"
              android:textColor="@color/colorAccent"
              android:textSize="25sp"/&gt;
      &lt;/android.support.v7.widget.Toolbar&gt;
  &lt;/android.support.design.widget.AppBarLayout&gt;
  
  &lt;FrameLayout
      android:id="@+id/fragment_loader"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      app:layout_behavior="@string/appbar_scrolling_view_behavior" /&gt;  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>fragment_loader loads "mother" fragment where tabLayout and viewPager are initialized</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:fitsSystemWindows="true"
  android:layout_width="match_parent"
  android:layout_height="match_parent"&gt;
  
  &lt;android.support.design.widget.TabLayout
      android:id="@+id/tabs"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@android:color/white"
      android:elevation="1dp"
      app:tabMode="fixed"
      app:tabGravity="fill" /&gt;
  
  &lt;android.support.v4.view.ViewPager
      android:id="@+id/viewpager"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:layout_below="@id/tabs" /&gt;&lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>viewPager contains two fragment and one of them actually works... it achieves my goal written above but one which has NestedScrollView with BottomSheetBehavior does not, plus NestedScrollView is hidden and when i scroll up with another fragment (which hasn`t NestedScrollView) and switch back to problematic one, then it shows (short: while toolbar is hidden NestedScrollView is shown)</p>
  
  <pre><code>&lt;android.support.v4.widget.NestedScrollView
          android:id="@+id/bottom_sheet"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:elevation="4dp"
          android:clipToPadding="true"
          android:background="@android:color/white"
          app:behavior_peekHeight="?attr/actionBarSize"
          app:layout_behavior="android.support.design.widget.BottomSheetBehavior"&gt;
  </code></pre>
  
  <p>so here is my whole code, once i removed BottomSheetBehavior and it worked fine but i need both: hiding toolbar and bottom sheet</p>