FairEmail/app/src/main/res/layout/activity_dsn.xml

<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".ActivityDSN">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <TextView
                android:id="@+id/tvHeaders"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="3dp"
                android:fontFamily="monospace"
                android:minHeight="60dp"
                android:text="Headers"
                android:textAppearance="@style/TextAppearance.AppCompat.Small"
                android:textIsSelectable="true"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <eu.faircode.email.ContentLoadingProgressBar
                android:id="@+id/pbWait"
                style="@style/Base.Widget.AppCompat.ProgressBar"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:indeterminate="true"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <androidx.constraintlayout.widget.Group
                android:id="@+id/grpReady"
                android:layout_width="0dp"
                android:layout_height="0dp"
                app:constraint_referenced_ids="tvHeaders" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>