Background color bug

Hello.

I’m designing my emails layout with this plugin:

https://wordpress.org/plugins/wp-html-mail/

I added a background color to my email template.
When I go to Mail Logging and press the View button, the background color fills the entire screen.

Here’s an example:
https://s18.postimg.org/ekjqaskd5/bug.png

It’s a minor bug, it gets fixed if the page is reloaded, but I thought I’d report it.

Please let me know.
Thanks!