Re: BC default dynamic menus

Using BC's 'default' [table+javascript]-based menu is asking for trouble; much better to use the simpler, more customisable and flexible [ul+css] versions.

The only workaround I've found to the issue of the submenu position is to apply position:fixed; to the container of the submenu items.

In your case:

.catdiv1559005 {
    position: fixed;
}

You'll also need to experiment with the menu's settings in the backend to get the layout right; particularly item width & height, and 'relative child position'.