Gah! Breaking basic navigation functionality, along with the clipboard, on page search functionality (i.e., basic application and OS level stuff), keyboard navi

Gah! Breaking basic navigation functionality, along with the clipboard, on page search functionality (i.e., basic application and OS level stuff), keyboard navigation, and common keyboard shortcuts and mouse/touch gestures, are amongst the absolute cardinal sins of web applications. These ought to be acceptance criteria for every single "story" implemented that impacts the client-side. Does anybody do it? Well, some, but very few.