There are options for personalizing the components of the Editor window. You can:
Remove the document structure column.
Change the colors associated with structure information.
Show/hide segment numbers.
Show/hide whitespace characters.
Show/hide standard formatting tags (by default, these are not displayed).
Show/hide text formatting.
Personalization options are located in the Options dialog box.
Overview: Editor View Display Preferences
Topic: Published: November 10, 2014