Most editors are divided into a series of expandable sections. These are a means of hiding and showing different amounts of information, so that you can choose exactly what information is immediately displayed to you.
Expandable sections can be expanded and collapsed by clicking on the little arrow to the left of their title:
Collapsed:
Expanded:
You can choose which sections are automatically expanded when an editor is opened.
In read-only editors you can also choose whether or not to see sections that have no data. Note that sections displaying categories are not displayed at all if there are not category values.
When you open the read-write equivalent editor Epic remembers which sections were expanded.
These are all examples of progressive disclosure.