Hello VMalinov,

The issue comes from the fact that FireFox does not have default "event" variable in the JavaScript engine. So when calling:

igmenu_showMenu(ctlFlagOffer_menuId, event);

under FireFox, we are calling this function with NULL or very limited "event" bject.
There are two approches here:

1. Explicitly supply X and Y coordinates (calculated by your logic) in this way:
igmenu_showMenu(ctlFlagOffer_menuId, null, x, y);

2. This one will have limited applicability, but it will work in certain scenarios. The idea is to get the original browser's event when calling igmenu_showMenu(). For example, if you havea button (or a link) with "onclick" handler defined like that:

<a href="#" onclick="myCustomFunction()" />
and then you have your custom function, that calls igmenu_showMenu():

function myCustomFunction()
{
 // do my logic here ...
  igmenu_showMenu(var_with_id, event);
}

This should be changed to:

<a href="#" onclick="myCustomFunction(event)" />

function myCustomFunction(e)
{
 // do my logic here ...
  igmenu_showMenu(var_with_id, e);
}

Now we have explicitly passed the original browser's event to our function, so we can pass it down to the igmenu_showMenu() function.

Hope this helps.