Steps to Reproduce: 1) Open firefox with New Profile. 2) Search for "print.use_simplify_page" in about:config and make the value true. (If it's not) 3) Navigate to a website which has Reader View. (eg. news.yahoo.com, bbc.com). 4) Click on an article from the page. 5) Go to Reader view. 6) Select Print option from menu. 7) Click the Simplify Page checkbox. (It works only for 1st time. Also checked from different pc) Actual Result: The checkbox can't be selected. Expected Result: It should be checked.