Mapbox map in dialog fragment

Question

I am trying to add a Mapbox map inside of a dialog fragment.I have successfully added it i but when I run my application, the map isn't bound by the dialog as can be seen in the image below:

I have followed the getting started tutorial for adding the map into my dialog fragment (Maps Android SDK)

Is there a way I can prevent the map from sliding off of the dialog?

Here is how I start the dialog:

DialogFragment myDialog= MyDialog.newInstance();
myDialog.show(getActivity().getSupportFragmentManager(), "my_dialog");

My dialog xml is as follows:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:custom="http://schemas.android.com/apk/res-auto"
xmlns:mapbox="http://schemas.android.com/tools"
android:id="@+id/fragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/backgroundGrey">

<ScrollView
    android:id="@+id/scrollView"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    ...

    <RelativeLayout
        android:id="@+id/mapContainer"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:gravity="center_vertical"
        android:layout_marginTop="8dp"
        android:orientation="vertical">

        <!-- Mapbox map -->
        <com.mapbox.mapboxsdk.maps.MapView
            android:id="@+id/mapView"
            android:background="#ffffff"
            android:layout_width="match_parent"
            android:layout_height="match_parent"/>

    </RelativeLayout>

    ...

</ScrollView>

Finally I initialize the map like so in my dialog:

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ...

    _mapView = (MapView) convertView.findViewById(R.id.mapView);
    _mapView.onCreate(savedInstanceState);
    _mapView.onResume();
    _mapView.getMapAsync(this);

    ...
}

@Override
public void onMapReady(MapboxMap mapboxMap) {
    this._mapboxMap = mapboxMap;
}