UI Issue on WYSIWYG Editor when editing Application Class

Steps to reproduce issue:

• login
• create a new application using App WIthin Minutes
• Insert a long text field type, edit it and select WYSIWYG Editor option
• finish creating the app

After, edit your application class (from the Application Homepage - the one with the livetable)

You will see the WYSIWYG Editor looks wierd.

Tested on Chrome