Warn us when token strings (e.g. {{ or }}) exist in Preheader.

Warn us when token strings (e.g. {{ or }}) exist in Preheader.

We can input tokens in Preheader, however these tokens do not work correctly in some cases.
Tokens aren't supported in the WYSIWYG preheader, so please consider to warn us when there are token strings (e.g. {{ or }} ) in Preherder.
https://docs.marketo.com/display/public/DOCS/Email+Editor+v2.0+Overview
Tokens do not work in the Preheader when using the email editor.