Small layout improvement

app/src/main/res/layout/action_button_text.xml

@@ -9,7 +9,7 @@
         style="@style/Widget.AppCompat.Toolbar.Button.Navigation"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:background="@android:color/transparent"
+        android:contentDescription="@string/title_encrypt"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent"
         app:srcCompat="@drawable/twotone_lock_24"