U.S. cable and satellite television operators, already locking horns with programmers over subscriber fees, are now squaring off over the mobile apps that viewers are increasingly using to watch TV. Internet-based services such as Netflix Inc have gotten millions of viewers accustomed to catching shows on tablets and phones. And as the incumbents are getting in on the act with apps of their own, that has become a sticking point dragging out major programming negotiations, as in the case of Dish Network Corp and Walt Disney Co, which are trying to reach a new rights agreement. Missteps by cable and satellite operators also raise the danger that some consumers will rely more on Netflix, and other such services, and cancel their pay-TV subscriptions, causing a major drop in industry revenue.