Don't show white spacing in summary / introduction field of a contenttype

When you open a document in the CMS (https://cms.demo.onehippo.com/), you see white spacing in the summary / introduction field of the news content type (see screenshot). You don't see this white spacing in the front end:
http://demopublic.onehippo.com/news/2010/07/melting-glacier-in-italy-gets-a-giant-thermal-blanket.html

This whitespacing will show up in all contenttype which have a summary / introduction field.