PartTwoActivity class layout file

part_two_activity.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"/>

    <LinearLayout
            android:id="@+id/toolbarContainer"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:background="?attr/colorPrimary">  <!-- added here -->

        <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"/> <!-- removed from here and tabs.xml -->

        <include layout="@layout/tabs"/>
    </LinearLayout>

</FrameLayout>