In order to make elements styled after updatepanel is updated, we just need to call myform_manager.refresh() inside OnUpdatePanel event of KoolAjax's UpdatePanel.
span style="color: #ff0000;">"/KoolAjax/koolajax.php""/KoolGrid/koolgrid.php""/KoolForm/koolform.php";
$koolajax->scriptFolder = $KoolControlsFolder."/KoolAjax""myform""/KoolForm""sunset""myform" method="post">
<style type="text/css""myupdatepanel""panel_class">
<content>
<fieldset style="width:200px;padding-bottom:10px;padding-left:5px;""decoration""height:5px;"></div>
<input id="chk1" name="chk1" type="checkbox""chk1">Football</label>
<br />
<input id="chk2" name="chk1" type="checkbox""chk2""chk3" name="chk1" type="checkbox""chk3">Volleyball</label>
<br /><br/>
<input id="btnSubmit" type="submit" value="Submit" />
</fieldset>
</content>
<loading image="<?php echo $KoolControlsFolder;?>/KoolAjax/loading/5.gif""text/javascript""OnUpdatePanel"
KoolForm FullVersion 1.8.0.2 released on 25/11/2016