Consistency

app/src/main/java/eu/faircode/email/AdapterMessage.java

@@ -2006,7 +2006,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
             clearActions();
 
             ibSeenBottom.setImageResource(message.ui_seen
-                    ? R.drawable.twotone_visibility_off_24 : R.drawable.twotone_visibility_24);
+                    ? R.drawable.twotone_mail_24 : R.drawable.twotone_drafts_24);
             ibSeenBottom.setVisibility(!(message.folderReadOnly || message.uid == null) ||
                     message.accountProtocol == EntityAccount.TYPE_POP
                     ? View.VISIBLE : View.GONE);

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

@@ -150,7 +150,7 @@
         android:tooltipText="@string/title_toggle_seen"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintTop_toBottomOf="@id/wvBody"
-        app:srcCompat="@drawable/twotone_visibility_24" />
+        app:srcCompat="@drawable/twotone_mail_24" />
 
     <include
         android:id="@+id/InAction"