Modalpopupextender gets hide for some time once checkchanged event fires?
<p>I have used ModalpopupExtender control in my web page. I have checkbox for selectall option with checkchanged event with checkboxlist control(With list of options). Whenever i check selectall option then all rest of the options gets selected &amp; modalpopup window gets invisible for little time &amp; again it comes visible as i used code in checkchanged event of selectall checkbox as follows:</p>

<pre><code>ModalPopupExtender1.Show();
</code></pre>

<p>But i want to keep modalpopup window as it is once checkbox for selectall is checked, dont want to disappears popup window &amp; display again.
I used C# &amp; asp.net.
Please help me to solve this problem.</p>
