The C1AccordionExtender control allows users to expand pane content from the top, bottom, left, or right. Simply set the ExpandDirection property to take advantage of this feature.
<cc1:C1AccordionExtender ID="Panel1_C1AccordionExtender" runat="server"
TargetControlID="Panel1" ExpandDirection="Right">
<h3>Pane 1</h3>
<div>
<p>
Pane 1 content here.
</p>
</div>
<h3>Pane 2</h3>
<div>
<p>
Pane 2 content here.
</p>
</div>
<h3>
Pane 3</h3>
<div>
<p>
Pane 3 content here.
</p>
</div>
<h3>
Pane 4</h3>
<div>
<p>
Pane 4 content here.
</p>
</div>
<cc1:C1AccordionExtender ID="Panel1_C1AccordionExtender" runat="server" TargetControlID="Panel1">
</cc1:C1AccordionExtender>
Select View | Properties Window in the Visual Studio menu.
Click the drop-down list at the top of the Properties window and select Panel1_C1AccordionExtender.
Click the drop-down arrow next to the ExpandDirection property and select Top, Right, Left, or Bottom.