Sometimes when you have menu sub-items in a .NET menu control they will be hidden behind an image if they happen to overlap. To fix this, set the z index of the dynamicMenu css class
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="menu.ascx.cs" Inherits="YANKEE_WEB.menu" %>
<asp:Menu ID="mnuYANKEE" runat="server" DataSourceID="SiteMapDataSource1"
Orientation="Horizontal" ForeColor="#8D4F59" Font-Names="Arial"
Font-Size="Medium" Font-Bold="True"
StaticBottomSeparatorImageUrl="~/Images/separator.gif"
StaticEnableDefaultPopOutImage="False"
DynamicBottomSeparatorImageUrl="~/Images/Menu_bottom_sep.jpg"
CssClass="menumain" onprerender="mnuYANKEE_PreRender" DynamicHoverStyle-BackColor="#CCCCFF">
<StaticMenuStyle HorizontalPadding="4px" />
<StaticSelectedStyle ForeColor="#8D4F59" />
<StaticMenuItemStyle HorizontalPadding="15px" />
<DynamicHoverStyle BackColor="#cdcdcd" ForeColor="#500000" Font-Overline="False"
Font-Underline="false" Font-Bold="true"/>
<DynamicMenuStyle BackColor="#FFFFFF" BorderColor="" CssClass="dynamicMenu" VerticalPadding="0px" HorizontalPadding="0px" />
<DynamicMenuItemStyle Width="200px" CssClass="dynamicMenuItem" Font-Size="5pt" ForeColor="#8D4F59" />
<StaticHoverStyle ForeColor="#500000" />
<Items>
<asp:MenuItem Text="Home" Value="Home"></asp:MenuItem>
</Items>
</asp:Menu>
Now the css class for the DynamicMenuStyle
.dynamicMenu {
text-align:left;
padding-left:0px;
font-size:small;
margin-left:15px;
margin-top:5px;
z-index:1000;
}