Well, a BorderLayout splitting allow to split in both directions.
As far as I can understand you need these icons to allow a user easily understand there is splitting.
Example
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<%@ Import Namespace="Ext.Net.Utilities" %>
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
if (!X.IsAjaxRequest)
{
string miniBottomUrl = this.ResourceManager1.GetWebResourceUrl(ResourceManager.ASSEMBLYSLUG + ".extjs.resources.images.default.layout.mini-bottom.gif"),
miniTopUrl = this.ResourceManager1.GetWebResourceUrl(ResourceManager.ASSEMBLYSLUG + ".extjs.resources.images.default.layout.mini-top.gif");
this.MiniBottomUrl.Value = miniBottomUrl;
this.MiniTopUrl.Value = miniTopUrl;
}
}
</script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Ext.Net Example</title>
<script type="text/javascript">
var onReady = function () {
var tpl = ".{0} \{ background-image: url('{1}');\}";
Ext.net.ResourceMgr.registerCssClass("mini-bottom", String.format(tpl, "mini-bottom", MiniBottomUrl.getValue()));
Ext.net.ResourceMgr.registerCssClass("mini-top", String.format(tpl, "mini-top", MiniTopUrl.getValue()));
};
var applyIcons = function (region) {
var splitEl = region.splitEl,
bottom = splitEl.createChild({
cls : "my-split mini-bottom",
html : " "
}),
top = splitEl.createChild({
cls : "my-split mini-top",
html : " "
});
splitEl.addClassOnOver("my-split-over");
};
</script>
<style type="text/css">
.my-split {
width: 35px;
height: 5px;
position: absolute;
top: 0px;
opacity: 0.5;
filter: alpha(opacity=50);
}
.mini-bottom {
left: 42%;
}
.mini-top {
left: 52%;
}
.my-split-over .mini-bottom, .my-split-over .mini-top {
opacity: 1;
-moz-opacity: 1;
filter: none;
}
</style>
</head>
<body>
<form runat="server">
<ext:ResourceManager ID="ResourceManager1" runat="server">
<Listeners>
<DocumentReady Handler="onReady();" />
</Listeners>
</ext:ResourceManager>
<ext:Hidden ID="MiniBottomUrl" runat="server" />
<ext:Hidden ID="MiniTopUrl" runat="server" />
<ext:Panel
runat="server"
Width="400"
Height="400"
Layout="BorderLayout">
<Items>
<ext:Panel runat="server" Region="Center" />
<ext:Panel
runat="server"
Region="South"
Height="200"
Split="true" />
</Items>
<Listeners>
<AfterLayout
Handler="applyIcons(this.layout.south);"
Single="true" />
</Listeners>
</ext:Panel>
</form>
</body>
</html>