<p>Why do elements with the CSS <code>position: fixed</code> applied to them cause Firefox to eat 100% CPU when scrolling the page they are in? And are there any workarounds?</p>

<p>I've noticed this behavior on a few sites, for example the notification bar at the top of the page on StackOverflow. I'm using Linux in case that matters.</p>

[{'answer_id': 67602, 'author': 'Gilles', 'author_id': 10024, 'author_profile': 'https://Stackoverflow.com/users/10024', 'pm_score': 0, 'selected': False, 'text': "<p>Are you sure that there's a direct link here? Have you created a static HTML page with fixed elements to verify your theory? Given how widely these CSS properties are used, I'd think someone else would have noticed it by now, whatever browser/OS you're running.</p>\n"}, {'answer_id': 67607, 'author': 'Jim', 'author_id': 8427, 'author_profile': 'https://Stackoverflow.com/users/8427', 'pm_score': 3, 'selected': False, 'text': '<p>This is <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=201307" rel="nofollow noreferrer">bug #201307</a>.</p>\n'}, {'answer_id': 67626, 'author': 'Community', 'author_id': -1, 'author_profile': 'https://Stackoverflow.com/users/-1', 'pm_score': 1, 'selected': False, 'text': '<p>This website has a fixed element "First time at Stack Overflow? Check out the FAQ!", and it\'s slow as hell in firefox. Works better with Opera and Chrome though.\nFF3, Windows XP, ATI.</p>\n'}, {'answer_id': 67630, 'author': 'ConroyP', 'author_id': 2287, 'author_profile': 'https://Stackoverflow.com/users/2287', 'pm_score': 3, 'selected': False, 'text': '<p>It\'s a bug reported in <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=201307" rel="noreferrer">bugzilla</a></p>\n\n<p>Apparently a work-around (with mixed reports of success..) is to <a href="http://ubuntuforums.org/showpost.php?s=6a1b84b5381937fac2f478508203098e&amp;p=3675924&amp;postcount=6" rel="noreferrer">disable smooth-scrolling</a></p>\n\n<blockquote>\n  <p>Just disable smooth scrolling in Edit > Preferences > Advanced.</p>\n</blockquote>\n'}, {'answer_id': 67639, 'author': 'rpetrich', 'author_id': 4007, 'author_profile': 'https://Stackoverflow.com/users/4007', 'pm_score': 1, 'selected': False, 'text': '<p>it eats CPU because the browser has to repaint the entire viewport every scroll change rather than just the newly visible area</p>\n'}, {'answer_id': 67679, 'author': 'Community', 'author_id': -1, 'author_profile': 'https://Stackoverflow.com/users/-1', 'pm_score': 2, 'selected': False, 'text': '<p>As already stated, this is bug <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=201307" rel="nofollow noreferrer">#201307</a>. The workaround is to disable smooth scrolling:</p>\n\n<p>Edit -> Prefrences -> Advanced -> General tab -> uncheck "Use smooth scrolling"</p>\n'}]
['https://Stackoverflow.com/questions/67588', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/-1/']