MouseOver Expand and Collapse

C1WebSplitter1_SplitContainer.ToggleExpand();

You can add onClick or onMouseOver events to the WebPanels of the splitter and toggle the splitter through this way.

<C1WebSplitter:C1WebSplitter ID="C1WebSplitter1" runat="server" Height="318px" SkinName="Default" Width="483px">
 <C1WebSplitter:C1WebPanel runat="server" onClick="dothis()" onMouseOver="dothis()">
 </C1WebSplitter:C1WebPanel>
 <C1WebSplitter:C1WebPanel runat="server" onClick="dothis()" onMouseOver="dothis()">
 </C1WebSplitter:C1WebPanel>
</C1WebSplitter:C1WebSplitter>

<script type="text/javascript">
    function dothis()
    {
        C1WebSplitter1_SplitContainer.ToggleExpand();
    } 
    </script>

Hope that helps,
Greg L