<html>
    <head>
      <base href="https://bugs.webkit.org/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - wheel event triggered only once per touchpad touch"
   href="https://bugs.webkit.org/show_bug.cgi?id=149526">149526</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>wheel event triggered only once per touchpad touch
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>WebKit
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>Safari 9
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Macintosh
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Mac OS X 10.11
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>Critical
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P2
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Event Handling
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>webkit-unassigned&#64;lists.webkit.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>m.goleb+bugzilla&#64;gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Open <a href="http://output.jsbin.com/mimiqi/">http://output.jsbin.com/mimiqi/</a> in Safari 9 and scroll using a MacBook touchpad. The counter at the top left shows how many times the wheel event is fired. In all browsers except Safari 9 (i.e. Chrome, Firefox, **even Safari 8**) the event is fired once per animation frame. Safari 9 USUALLY fires it only once per touching the touchpad, although sometimes it switches into once-per-frame mode (scroll a little in various directions and you should see it).

This will break many interactions that depend on wheel happening in every animation frame to provide a custom scroll-like UI.

Note that I can't reproduce this new broken behavior on JSFiddle which may mean it doesn't happen in iframes (the test case is identical): <a href="http://jsfiddle.net/eoxzpqn5/">http://jsfiddle.net/eoxzpqn5/</a>

Is there any chance of this getting fixed in Safari 9? Seems pretty severe to me. :(</pre>
        </div>
      </p>
      <hr>
      <span>You are receiving this mail because:</span>
      
      <ul>
          <li>You are the assignee for the bug.</li>
      </ul>
    </body>
</html>