Prevent Flicker from Ajax CollapsiblePanelExtender on Postback

Let’s see how to fix the flickering of the CollapsiblePanelExtender when collapsed is set to true (Collapsed="true")

Here is my CollapsiblePanelExtender

<cc1:CollapsiblePanelExtender ID="CollapsePanel1" runat="server" SuppressPostBack="true" CollapseControlID="btnCancel" Collapsed="true" CollapsedText="Show Time" ExpandControlID="imgPostQuestion" ExpandedText="Hide Time" TargetControlID="panelPost"> cc1:CollapsiblePanelExtender>

Your TargetPanel is here

<asp:Panel ID="panelPost" runat="server" CssClass="cpBody">

<div>

//Ur collapsible Content

div>

asp:Panel>

And now we are preventing the flickering by the CSS style and the style is as follows.

.cpBody

{

height:0px;

overflow: hidden;

}