Does anyone know if IE 'return false'?

This simple test code works in all browsers except IE (tested in IE8):

#dBox {
    height:100px;
    width: 230px;   
    overflow-y:auto;    
}

$(function () { 
    $('#s').focus(function(){  
        $(this).after('<ul id="dBox"></ul>');  
        for (i=0;i<10;i++) $('#dBox').append('<li>'+i+'</li>');
    });
    $('#dBox').live('mousedown',function(event) {  
        //event.stopPropagation();  
        //event.preventDefault();  
        //console.log  (event.isDefaultPrevented());  
        //event.stopImmediatePropagation();  
        return false;   
     });  
    $('#s').blur(function () { $('#dBox').remove();  });
});     
<input type="text" id="s"/>

I've tried all the options from live fn., but no luck.
On event.isDefaultPrevented() it returns true, but #dBox it's still removed.
I've even tried to bind a regular mousedown inside the focus fn. But the same result it's working in all browsers but not IE.
Does anyone have any idea of what's wrong?

This is directly because of Event Delegation with jQuery live() binding events using live does not bind the direct element. Instead it attaches a handler on the root node of the document.

The .live() method is able to affect elements that have not yet been added to the DOM through the use of event delegation: a handler bound to an ancestor element is responsible for events that are triggered on its descendants. The handler passed to .live() is never bound to an element; instead, .live() binds a special handler to the root of the DOM tree. In our example, when the new element is clicked, the following steps occur:

Assuming you want to keep focus on the input when the #dBox element is clicked this will work and here is a demo http://www.jsfiddle.net/WurDE/

Note: if you do not want to retain focus on the input then remove the trigger('focus') from the code.

$(function () {
    $('#s').focus(function(){
        if (!$('#dBox').length) {
          var $dbox = $('<ul id="dBox"></ul>');
          for (i=0;i<10;i++) $dbox.append('<li>'+i+'</li>');
          $(this).after($dbox);
          $dbox.bind("mousedown", function() {
            $('#s').unbind('blur')
          });
          $dbox.bind("mouseup", function() {
            $('#s').bind('blur', function () {
              $('#dBox').remove();  
            }).trigger('focus');
          });
        }
    });

    $('#s').bind('blur', function () {
      $('#dBox').remove();  
    });
});