Page refresh after postback in UpdatePanel on Sharepoint 2013 publishing page - asp.net

Question

When I try to execute a second xmlhttprequest in UpdatePanel on sharepoint 2013 in firefox before the first one is finished, I get whole page refresh.
First request status is Aborted.
Second request response is:
1|#||4|97|pageRedirect||%2f_login%2fdefault.aspx%3fReturnUrl%3d%252fsites%252ftest%252fPages%252fUpdatePanelTest.aspx|
This error can be reproduced with the attached code (clicking the button twice quickly produces the error).
This problem occurs only if I place Web Part with this control on Publishing page on Sharepoint 2013.
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="TestUpdatePanel.ascx.cs"
Inherits="Example.TestUpdatePanel" %><asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
<asp:CheckBoxList runat="server" ID="CheckboxList1" AutoPostBack="true">
<asp:ListItem Text="CheckBox1" Value="valueFromCheckBox1" />
<asp:ListItem Text="CheckBox2" Value="valueFromCheckBox2" />
<asp:ListItem Text="CheckBox3" Value="valueFromCheckBox3" />
<asp:ListItem Text="CheckBox4" Value="valueFromCheckBox4" />
<asp:ListItem Text="CheckBox5" Value="valueFromCheckBox5" />
</asp:CheckBoxList>
</ContentTemplate></asp:UpdatePanel><asp:UpdatePanel ID="UpdatePanel2" runat="server">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="CheckboxList1" EventName="SelectedIndexChanged" />
</Triggers>
<ContentTemplate>
<asp:Label ID="Label2" runat="server" Text="Label"></asp:Label>
<asp:Button ID="Button2" runat="server" OnClick="Button2_Click" Text="Button" />
<br />
<asp:Label ID="Label3" runat="server" Text="Label"></asp:Label>
</ContentTemplate></asp:UpdatePanel>
protected void Page_Load(object sender, EventArgs e)
{
CheckboxList1.SelectedIndexChanged += CheckboxList1_SelectedIndexChanged;
}
private void CheckboxList1_SelectedIndexChanged(object sender, EventArgs e)
{
System.Threading.Thread.Sleep(3000);
Label3.Text = CheckboxList1.SelectedValue;
}
protected void Button1_Click(object sender, EventArgs e)
{
System.Threading.Thread.Sleep(3000);
Label1.Text = "Button1_Click";
}
protected void Button2_Click(object sender, EventArgs e)
{
System.Threading.Thread.Sleep(3000);
Label2.Text = "Button2_Click";
}

Answer 1

Do you intentionally want to allow the user to submit a postback request while there is already a request going on? If this is unintentional, you may want to consider disabling user controls while a server sided method is running. This can be accomplished with the UpdateProgress control. The idea is that you can use this control to pop up a div that covers the entire application while a post back is occurring. It can be used like this:
<asp:UpdateProgress ID="UpdateProgress1" AssociatedUpdatePanelID="UpdatePanel1" runat="server" >
<ProgressTemplate >
<div id="wait" style="width:100%; height:100%;
position:absolute; top:0; left:0; z-index:1000;background-color: #666699;
filter: alpha(opacity=80); text-align:center; vertical-align:middle;">
<div style="border:5px solid black; width:200px; height:50px;
background- color:White; top:50%; position:absolute;">
Saving changes. Please wait...
</div>
</div>
</ProgressTemplate>
</asp:UpdateProgress>

Answer 2

By default the updatepanels won't work in SP 2013. You have to follow the below article where there is a fix:
http://msdn.microsoft.com/en-us/library/bb861877.aspx