title: Android Support Design Library: Toolbar collapses in 4.1
body: <p>After updating Android Support Design Library version, I found this bug.
  In place of empty area, toolbar should have been displayed.</p>
  
  <p>When I scroll up and down, the toolbar does not appear, blank area replaces the toolbar.</p>
  
  <p>Please tell me what is the problem ?</p>
  
  <p><a href="https://i.stack.imgur.com/e9rGW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/e9rGW.png" alt="Normal, start state"></a></p>
  
  <p><a href="https://i.stack.imgur.com/0GyhI.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0GyhI.jpg" alt="Bug after SnackBar dissmiss"></a></p>
  
  <blockquote>
    <p><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:id="@+id/main_content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"&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.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_scrollFlags="scroll|enterAlways" /&gt;
        &lt;/android.support.design.widget.AppBarLayout&gt;
        &lt;android.support.v7.widget.RecyclerView
            android:id="@+id/TaskTypes"
            android:scrollbars="vertical"
            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></p>
  </blockquote>