title: ToolBar cannot scroll off the screen thoroughly even if I used NestedScrollView
body: <p>I would like the TabLayout to stay in screen and the ToolBar to be off screen when scrolling, but the ToolBar has always got some part staying in the screen. I searched some codes on the Internet and run them but they have the same result.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.design.widget.CoordinatorLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"
  tools:context="com.ihandy.a2014011385.MainActivity"&gt;
  
  &lt;android.support.design.widget.AppBarLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
      &lt;android.support.v7.widget.Toolbar
          android:id="@+id/toolbar"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:background="?attr/colorPrimary"
          app:popupTheme="@style/AppTheme.PopupOverlay"
          app:layout_scrollFlags="scroll|enterAlwaysCollapsed"/&gt;
  
      &lt;android.support.design.widget.TabLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:id="@+id/channels_tabs"&gt;
      &lt;/android.support.design.widget.TabLayout&gt;
  
  &lt;/android.support.design.widget.AppBarLayout&gt;
  
  &lt;android.support.v4.widget.NestedScrollView
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:paddingBottom="@dimen/activity_vertical_margin"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      app:layout_behavior="@string/appbar_scrolling_view_behavior"
      tools:context="com.ihandy.a2014011385.MainActivity"
      tools:showIn="@layout/app_bar_main"&gt;
  
      &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:orientation="vertical"&gt;
  
          &lt;TextView
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:text="@string/large_text"/&gt;
      &lt;/LinearLayout&gt;
  
  &lt;/android.support.v4.widget.NestedScrollView&gt;
  
  &lt;android.support.design.widget.FloatingActionButton
      android:id="@+id/fab"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="bottom|end"
      android:layout_margin="@dimen/fab_margin"
      android:src="@android:drawable/ic_dialog_email" /&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>and java code</p>
  
  <pre><code>TabLayout channels = (TabLayout)findViewById(R.id.channels_tabs);
  channels.setTabMode(TabLayout.MODE_SCROLLABLE);
  channels.addTab(channels.newTab().setText("123"));
  channels.addTab(channels.newTab().setText("123"));
  channels.addTab(channels.newTab().setText("123"));
  </code></pre>
  
  <p>This is the effect now</p>
  
  <p><a href="https://i.stack.imgur.com/l8iie.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/l8iie.png" alt="enter image description here"></a></p>