If you’re using the Chrome extension, once it’s open within a tab, it will keep re-opening on each new page loaded within that tab until you click Menu → Close.
Would you like it to always open the Web Reader for web-sites that it knows are in the language you’re learning?
Maybe every time you open the Web Reader on a web-site, it could add that web-site to a list, and always re-open the Web Reader whenever you visit one of those sites in future. What do you think?