title: "undefined handler" from prototype.js line 3877
body: <p>A very niche problem:</p>
  
  <p>I sometimes (30% of the time) get an 'undefined handler' javascript error on line 3877 of the prototype.js library (version 1.6.0.2 from google: <a href="http://ajax.googleapis.com/ajax/libs/prototype/1.6.0.2/prototype.js" rel="nofollow noreferrer">http://ajax.googleapis.com/ajax/libs/prototype/1.6.0.2/prototype.js</a>).</p>
  
  <p>Now on this page I have a Google Map and I use the Prototype Window library.</p>
  
  <p>The problem occurs in IE7 and FF3.</p>
  
  <p>This is the info FireBug gives:</p>
  
  <pre><code>handler is undefined
  ? in prototype.js@3871()prototype.js (line 3877)
  handler.call(element, event);
  </code></pre>
  
  <p>I switched to a local version of prototypejs and added some debugging in the offending method (createWraper) but the debugging never appears before the error...</p>
  
  <p>I googled around and found 1 other mention of the error on the same line, but no answer so I'm posting it here where maybe, some day someone will have an answer :).</p>