Spry menu with 1px (line? shift?) down in IE7

Question

Hi. I built a spry menu that works great on my Mac using Safari, Opera, Firefox, Flock, Navigator. But on my PC, using IE7, there appears a 1px (white) line at the top of the menu. At first, I thought IE7 was shifting the menu down 1px. But I see a 1px (white) line between (at the top of) each submenu item, and think it may be the same issue. Can anyone help?
Thanks.
Here's the example: http://www.ontherise.org/Rev/
Here's the css I'm using for the menu:
@charset "UTF-8";
/* SpryMenuBarHorizontal.css - version 0.6 - Spry Pre-Release 1.6.1 */
/* Copyright (c) 2006. Adobe Systems Incorporated. All rights reserved. */
LAYOUT INFORMATION: describes box model, positioning, z-order
/* The outermost container of the Menu Bar, an auto width box with no margin or padding */
ul.MenuBarHorizontal
padding: 0;
list-style-type: none;
font-size: 100%;
cursor: default;
width: auto;
margin-top: 0;
margin-right: 0;
margin-bottom: 0;
margin-left: 12px;
list-style-image: none;
text-decoration: none;
/* Set the active Menu Bar with this class, currently setting z-index to accomodate IE rendering bug: http://therealcrisp.xs4all.nl/meuk/IE-zindexbug.html */
ul.MenuBarActive
z-index: 1000;
/* Menu item containers, position children relative to this container and are a auto width that stretches to accomodate text */
ul.MenuBarHorizontal li
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
position: relative;
text-align: left;
cursor: pointer;
width: auto;
float: left;
list-style-image: none;
text-decoration: none;
/* Submenus should appear below their parent (top: 0) with a higher z-index, but they are initially off the left side of the screen (-1000em) */
ul.MenuBarHorizontal ul
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
z-index: 1020;
cursor: default;
width: 19em;
position: absolute;
left: -1000em;
text-decoration: none;
/* Submenu that is showing with class designation MenuBarSubmenuVisible, we set left to auto so it comes onto the screen below its parent menu item */
ul.MenuBarHorizontal ul.MenuBarSubmenuVisible
left: auto;
/* Menu item containers are same fixed width as parent */
ul.MenuBarHorizontal ul li
width: 19em;
/* Submenus should appear slightly overlapping to the right (95%) and up (-5%) */
ul.MenuBarHorizontal ul ul
position: absolute;
margin: -5% 0 0 95%;
/* Submenu that is showing with class designation MenuBarSubmenuVisible, we set left to 0 so it comes onto the screen */
ul.MenuBarHorizontal ul.MenuBarSubmenuVisible ul.MenuBarSubmenuVisible
left: auto;
top: 0;
DESIGN INFORMATION: describes color scheme, borders, fonts
/* Submenu containers have borders on all sides */
ul.MenuBarHorizontal ul
border: 1px solid #FFFFFF;
/* Menu items are a red block with padding and no text decoration. Stephen added the ul.MenuBarHorizontal a:visited to keep the same treatment for visited links */
ul.MenuBarHorizontal a, ul.MenuBarHorizontal a:visited
display: block;
cursor: pointer;
background-color: #992E2E;
color: #FFFFFF;
font-weight: bold;
text-decoration: none;
padding-top: 0.5em;
padding-right: 2em;
padding-bottom: 0.2em;
padding-left: 0.5em;
text-decoration: none;
/* Stephen added this  id selector so a clicked main tab would remain a white block*/
#clicked
background-color: #FFFFFF;
color: #000000;
text-decoration: none;
/* Menu items that are open with submenus are set to MenuBarItemHover with a white background and black text */
ul.MenuBarHorizontal a.MenuBarItemHover, ul.MenuBarHorizontal a.MenuBarItemSubmenuHover, ul.MenuBarHorizontal a.MenuBarSubmenuVisible
background-color: #FFFFFF;
color: #000000;
text-decoration: none;
/* Menu items that have mouse over or focus have an orange background and black text. Stephen added the ul.MenuBarHorizontal a:hover#clicked so the hover highlight color would appear when you mouse over a clicked state main menu item */
ul.MenuBarHorizontal a:hover, ul.MenuBarHorizontal a:focus,
ul.MenuBarHorizontal a:hover#clicked
background-color: #FFCC66;
color: #000000;
text-decoration: none;
SUBMENU INDICATION: styles if there is a submenu under a given menu item
/* Menu items that have a submenu have the class designation MenuBarItemSubmenu and are set to use a background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal a.MenuBarItemSubmenu
background-image: url(SpryMenuBarDown.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
/* Menu items that have a submenu have the class designation MenuBarItemSubmenu and are set to use a background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal ul a.MenuBarItemSubmenu
background-image: url(SpryMenuBarRight.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
/* Menu items that are open with submenus have the class designation MenuBarItemSubmenuHover and are set to use a "hover" background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal a.MenuBarItemSubmenuHover
background-image: url(SpryMenuBarDownHover.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
/* Menu items that are open with submenus have the class designation MenuBarItemSubmenuHover and are set to use a "hover" background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal ul a.MenuBarItemSubmenuHover
background-image: url(SpryMenuBarRightHover.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
BROWSER HACKS: the hacks below should not be changed unless you are an expert
/* HACK FOR IE: to make sure the sub menus show above form controls, we underlay each submenu with an iframe */
ul.MenuBarHorizontal iframe
position: absolute;
z-index: 1010;
filter:alpha(opacity:0.1);
/* HACK FOR IE: to stabilize appearance of menu items; the slash in float is to keep IE 5.0 from parsing */
@media screen, projection
ul.MenuBarHorizontal li.MenuBarItemIE
display: inline;
f\loat: left;
background: #FFF;

Answer 1

I guess the real question is: is there any reason IE7 would add a 1px white line at the top of the main menu and each submenu?