k-9/res/layout/folder_list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_height="fill_parent"
    android:layout_width="fill_parent"
    android:background="?android:attr/colorBackground">
    <ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        />

</LinearLayout>