Hi,

Rendering of splitter is based on css classes. To customize appearance of splitter bar, you may modify classes in ig_splitter.css or customize a specific control using SplitterBar property.

<style type="text/css">
.barWidthCss
{
  width:20px;
}
.barShadowCss
{
  background:#E0E0E0;
}
.barCss
{
  background:#A0C0E0;
}
</style>

<ig:WebSplitter ID="WebSplitter1" runat="server" Height="140px" Width="300px">
  <SplitterBar ThicknessCssClass="barWidthCss" CssClass="barCss" ShadowCssClass="barShadowCss"></SplitterBar>
  <Panes>
    <ig:SplitterPane runat="server"></ig:SplitterPane>
    <ig:SplitterPane runat="server"></ig:SplitterPane>
  </Panes>
</ig:WebSplitter>