Required to use <a href="http://www.w3.org/TR/pointerlock/">Pointer Lock</a> via calls to <code>webkitRequestPointerLock</code> or Pepper's <a href="https://developers.google.com/native-client/peppercpp/classpp_1_1_mouse_lock"> Mouse Lock API</a>. See <a href="api_other.html">Other APIs</a> for behavior differences.