Feature addition: An option to change the size of the margin: Reading long lines on a large monitor is uncomfortable.
When used on a large screen (22" in my case), the Enhanced HTML article is displayed in very long lines. Each line is around 35cm long. This makes reading quite difficult for the eye.
Adding an option to change the size of the margin (or better, doing automatically depending on the screen size) would solve the issue.
You can make your window smaller, thus requiring no additional programming effort from Wiley.
No matter the size of my screen I read [dense] text in a window of between 7" - 9" wide, depending on the width of margin info that I may want to keep in view. Perhaps because it approximates text area on a printed page I find it quite comfortable for sustained reading, and it can be easily magnified by using the zoom option (in the status bar--Windows) if you'd like a larger font size.