Relative Layout com FAB

Estou tendo problemas ao arrastar o floatingActionButton, isso mesmo depois de mudar para RelativeLayout. Segue o código do arquivo xml da activity_main.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/floatingActionButton4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:clickable="true"
        app:srcCompat="@drawable/ic_launcher_foreground" />
    <ListView
        android:id="@+id/activity_main_lista_de_alunos"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </ListView>
</RelativeLayout>