title: Collapsing toolbar not collapsing when scrolled
body: <p>I am trying to implement collapsing toolbar in my android application. I am able to show the toolbar the way I want it to , but it is not collapsing when I scroll. </p>
  
  <p>I am using below code</p>
  
  <p><strong>activity.xml</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout 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"
  android:orientation="vertical"
  tools:context=".MainActivity"&gt;
  
  &lt;include layout="@layout/main_toolbar" /&gt;
  
  &lt;LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical"
      app:layout_behavior="@string/appbar_scrolling_view_behavior"&gt;
  
      &lt;com.gigamole.navigationtabstrip.NavigationTabStrip
          android:id="@+id/nts_strip"
          android:layout_width="match_parent"
          android:layout_height="30dp"
          android:background="@color/colorPrimary"
          android:elevation="4dp"
          app:nts_active_color="@color/white"
          app:nts_animation_duration="300"
          app:nts_color="@color/white"
          app:nts_corners_radius="1.5dp"
          app:nts_inactive_color="@color/white_transparent"
          app:nts_titles="@array/nts_titles" /&gt;
  
      &lt;android.support.v4.view.ViewPager
          android:id="@+id/pager_photos"
          android:layout_width="match_parent"
          android:layout_height="0dp"
          android:layout_weight="1"
          android:background="@color/white_transparent" /&gt;
  &lt;/LinearLayout&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p><strong>main_toolbar.xml</strong></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"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  app:layout_collapseMode="parallax"
  android:orientation="vertical"&gt;
  
  &lt;android.support.design.widget.AppBarLayout
      android:id="@+id/appBar"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"&gt;
  
      &lt;android.support.design.widget.CollapsingToolbarLayout
          android:id="@+id/collapsingToolbar"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          app:layout_scrollFlags="scroll|enterAlwaysCollapsed"&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/toolbar"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:background="@color/colorPrimary"
              app:layout_collapseMode="pin"
              app:layout_scrollFlags="scroll|enterAlways"
              app:popupTheme="@style/ThemeOverlay.AppCompat.Light"&gt;
  
              &lt;TextView
                  android:id="@+id/tv_toolbar_title"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent"
                  android:gravity="center_vertical"
                  android:textAppearance="?android:attr/textAppearanceLarge"
                  android:textColor="@color/white" /&gt;
          &lt;/android.support.v7.widget.Toolbar&gt;
      &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
  &lt;/android.support.design.widget.AppBarLayout&gt;
  </code></pre>
  
  <p></p>
  
  <p>below is how the screen looks like</p>
  
  <p><a href="https://i.stack.imgur.com/meo3f.png" rel="noreferrer"><img src="https://i.stack.imgur.com/meo3f.png" alt="enter image description here"></a></p>