<script>
function foo() {
    var timeout = setTimeout(function() { alert("This should not happen. If you do see this alert, then timers on the page are firing while paused!") }, 0);
    debugger;
    clearTimeout(timeout);
}

setTimeout(foo, 100);
</script>
<p>Test for <a href="https://bugs.webkit.org/show_bug.cgi?id=20042">Bug 20042: UI frozen when the debugger is paused</a>.</p>
<p>Open the inspector and start debugging in the Scripts panel. While paused, try to open the Console. The Console should animate open fully.</p>