In Entity view, if a Button/script appends content to a displayed Rich Text field (e.g. Description), the field automatically expands to display the new, longer content.
However, if the content cannot fit in the current window height, the Rich Text will fill the entire window height, and now it is no longer possible to scroll down below the field (i.e. to see the Collections fields below) - scrolling stops at the bottom of the Rich Text field.
Refreshing the page fixes this.