I have a vertical IG menu in a left-of-page <div>, the ID of which identifies the CSS style. It has a single pixel right border and a light grey background:

When I click on a top-level node that has a child item, the screen is re-rendered thus:

The black border has disappeared below the menu flyout and the grey background has turned white in the <div> area below the menu.

The following pertains:

• The menu is on a Master Page (probably not relevant, but I'm in straw-clutching territory on this one)
• The styles are largely defined by an external CSS file
• The above problem does not occur every time (about 70%)
• The above problem does not appear to be related to the type of menu ExpandEffect. I have tried: [Slide], [Fade] and [Not Set].
• The menu is populated dynamically via C# program code. The menu is not directly bound to a data source, rather, a program reads records from a database table and uses them to populate the menu via Node.Add method calls.
• The menu is populated on the initial Page Load event of the containing page
• In all other regards, the menu appears to be behaving as expected.

Here is the declaration of the menu:

<div id="leftnavbar">
  <ignav:UltraWebMenu ID="LeftMenu" runat="server" CssClass="vertMenu"
    BorderCollapse="True" ExpandEffects-Type="Slide" WebMenuTarget="VerticalMenu">
    <Images><XPSpacerImage Width="1px"/></Images>
    <ExpandEffects Type="NotSet" ShadowColor="#888888"></ExpandEffects>
    <MenuClientSideEvents ItemClick="LeftMenu_ItemClick"></MenuClientSideEvents>
  </ignav:UltraWebMenu>
</div>

Here is the definition of the CSS style that defines the containing <div>:

leftnavbar {
 position: absolute;
 left: 0em;
 top: 90px;
 font-size: small;
 font-weight: normal;
 width: 225px;
 border-right: 1px solid Black;
 float: left;
 padding-left: 0px;
 font-family: Verdana, Geneva, Arial, Helvetica, sans-serif;
 height: 100%;
 background-color: #e3e6eb;
 text-align: left;
 margin: 1px;
}

Any suggestions or assistance would be gratefully received.

Kind regards

Paul

MS VS2008 Pro. IG for Web 2008v1. C#