Created Issue: Change from _postBackSettings.panelID [27067]

I was using this in ajax then I updated to the new version for (asp.net 3.5 VS2008)

var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(initializeRequest);
prm.add_endRequest(endRequest);
var postbackElement;
function initializeRequest(sender, args) {
if(prm._postBackSettings.panelID.lastIndexOf("fvSchedule")>1) {
this line errors
why did this change to
prm._postBackSettings.asyncTarget