Answered on StackOverflow: https://stackoverflow.com/a/53569023/116472 (basically the same answer as David)
You received this message because you are subscribed to the Google Groups "GWT Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to email@example.com.
To post to this group, send email to firstname.lastname@example.org.
Visit this group at https://groups.google.com/group/google-web-toolkit.
For more options, visit https://groups.google.com/d/optout.