The flyout-menu.xml is a bare-bones XML format (just enough to ensure that xml_parser_create() and the xml_parse() functions can establish the menu heirarchy). There is no associated XML schema needed for those functions, so none was generated with the initial release back in 18-Mar-2008.
As for the missing top line around the first entry, that's likely a CSS change from the original author's HTML/CSS menu script that was originally used (with permission) as the prototype for the structure of the generated CSS/HTML.
http://www.cssplay.co.uk/menus/flyout_4level.htmlThe CSS in question is in flyout-menu.php
/* style the links */
.flyoutmenu a, .flyoutmenu a:visited {
display:block;
text-decoration:none;
line-height: 1.8em;
width:95px; /* mchallis changed for adjusting firefox link width */
color:{$LC};
padding: 0 2px 0 5px;
border:1px solid {$BC};
border-width:0 1px 1px 1px;
}
the border-width: 0 1px 1px 1px directive causes the top border to not show. it was done that way to prevent a 2px border between entries from showing (which looked kinda clunky). Change it to
border-width:1px 1px 1px 1px;
to see the effect.
You could try using
border-width:0.5px 1px 0.5px 1px;
instead to see if that is more pleasing to your eye.