I find this service useful and the plugin nice. However, I experienced an issue and I found no place where to report it.
The issue: the plugin create a wrapper around the email field (class fx-relay-email-input-wrapper) with z-index of 99999999999999.
The label of that field was supposed to be over the field (z-index 100), but is actually hidden by the field itself (that normally has a z-index of 10) and this breaks the layout.
Thank you to consider this scenario in your tests.