No shadow on toolbar for pre-lollipop devices

Question

I'm using the design support library for creating a Toolbar (instead of default ActionBar, provided by AppCompatActivity), but I have a problem with displaying a shadow under it. As it says here you can wrap your toolbar in AppBarLayout to generate drop shadow, but somehow it doesn't work on my 4.4 device. I also followed this guide (step 6) and did exactly the same but it doesn't work either. The default ActionBar has the shadow, but unfortunatelly I can't use it.

Here's my activity in the manifest:

<activity android:name=".View.Activities.CommonPreferencesActivity"
        android:theme="@style/AppTheme.NoActionBar">
</activity>

Style for that activity (needed to hide default ActionBar):

<style name="AppTheme.NoActionBar">
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
</style>

Layout file:

<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:id="@+id/activity_common_preferences"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/main_background"
    tools:context="com.example.View.Activities.CommonPreferencesActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.Toolbar
            android:id="@+id/settingsToolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/toolbar_background"
            app:titleTextColor="@color/white"
            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>
    </android.support.design.widget.AppBarLayout>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/preferencesList"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/appBar"
        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" />
</android.support.design.widget.CoordinatorLayout>

And finally how I set that toolbar in code:

toolbar = (Toolbar) findViewById(R.id.settingsToolbar);
setSupportActionBar(toolbar);