Android Studio designer preview different to phone
<p>I'm new to android studio and developing on the android platform. I'm having a problem where the Android Studio designer preview doesn't show exactly what is on my phone. It shows an extra Toolbar widget at the top of the screen. I've had a look in the XML file for the activity and cannot find where it is coming from. It would be much appreciated if one of you could help.</p>

<p>Designer: <a href="http://imgur.com/A4TZFWb" rel="nofollow">http://imgur.com/A4TZFWb</a></p>

<p>Phone: <a href="http://imgur.com/kxP4CFn" rel="nofollow">http://imgur.com/kxP4CFn</a></p>

<p>This is a snippet from the XML file: </p>

<pre><code>&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.tomnulty.helloworld.SecondActivity"&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="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" /&gt;

&lt;/android.support.design.widget.AppBarLayout&gt;
</code></pre>

<p>And this is a snippet from the AndroidManifest file: </p>

<pre><code> &lt;activity
        android:name=".SecondActivity"
        android:label="@string/hello_world"
        android:theme="@style/AppTheme.NoActionBar"&gt;
        &lt;intent-filter&gt;
            &lt;action android:name="android.intent.action.SECOND" /&gt;

            &lt;category android:name="android.intent.category.DEFAULT" /&gt;
        &lt;/intent-filter&gt;
    &lt;/activity&gt;
</code></pre>