<asp:CollapsiblePanelExtender ID="CollapsiblePanelExtender1" runat="server" 
 TargetControlID="Panel2" Collapsed="True" ExpandControlID="Label1" 
 CollapseControlID="Label1" 
 CollapsedText="[Kliknij, aby rozwin¹ę]"
 ExpandedText="[Kliknij, aby zwin¹ę]" 
 TextLabelID="Label1">
</asp:CollapsiblePanelExtender>
