Generate context menu

Hi all,

I had already developed the js code that allowed me to display the context menu through another action. For example, by left clicking or pressing a key.
I managed to do what I wanted for most elements except for some like the mails in gmail or hotmail. When you right-click, there is a small menu with “archive” or “mark as unread” for example. It’s not the classic menu which appears.
What I would like to do is force the display of the classic menu on these too.
Here is the code I have so far to generate my contextmenu event :

window.document.addEventListener("click", associate, false);
window.document.addEventListener("mousedown", associate, false);
window.document.addEventListener("mouseup", associate, false);

var associate = function(event)
{
    var element = event.srcElement||event.target;
    element.addEventListener("click", context, true);
    element.addEventListener("mousedown", context, true);
    element.addEventListener("mouseup", context, true);
};

var context = function(event)
{
    if(event.button == 0)
    {
        var element = event.srcElement||event.target;
        menu(element, event);
        event.stopPropagation();
        event.preventDefault();
    }
};

var menu = function(element, event)
{
    var evt = element.ownerDocument.createEvent('MouseEvents');
    var RIGHT_CLICK_BUTTON_CODE = 2;
    evt.initMouseEvent('contextmenu', true, true, element.ownerDocument.defaultView, 1, event.screenX, event.screenY, event.clientX, event.clientY, false, false, false, false, RIGHT_CLICK_BUTTON_CODE, null);
    element.dispatchEvent(evt);
}; 

With that, on an email in gmail for example I still have the special gmail context menu when I left click.
Do you have any idea about how I could do ?