ASP.NET Splitter - Initial collapsed panel

Click on the arrow of the splitter separator.
The left panel of the splitter will expand.
Click again to collapse the left panel back.


The feature also works in horizontal splitter.

ASP.NET

    <obspl:Splitter CollapsePanel="left" id="spl1" runat="server" StyleFolder="styles/default">
        <LeftPanel>
            <Content>
                ... Left Panel content here ...

VB.NET
spl1.CollapsePanel = VerticalCollapsePanelType.left


C#
spl1.CollapsePanel = VerticalCollapsePanelType.right;


JavaScript
spl1.CollapsePanel("left");
spl1.ExpandPanel("right");