Hi,
    I am using two rad window objects .

<

telerik:RadWindowManager ID="RadWindowManager1" runat="server" Visible="true" ShowContentDuringLoad="false" CssClass="windowcontent"

 

 

BackColor="AliceBlue" Skin="IELSkin" EnableEmbeddedSkins="false" ForeColor="#ff0033" VisibleStatusbar="false" Modal="true" ReloadOnShow="true" Behaviors="Resize,Maximize,Close" Width="350px" Height="300px">

 

 

<Windows>

 

 

<telerik:RadWindow ID="Radwindow1" runat="server" Modal="true" Width="440px" Height="290px" Title ="Upload File" Behavior="Minimize,Reload,Close" ></telerik:RadWindow>

 

 

<telerik:RadWindow ID="Radwindow2" runat="server" VisibleStatusbar="false" Modal="true" Width="500px" Height="350px" Title ="Comments" Behavior="Minimize,Reload,Close" ></telerik:RadWindow>

 

 

</Windows>

 

 

</telerik:RadWindowManager>

After opening both  windows i am getting following error
Error: Sys.ArgumentOutOfRangeException: Value must be an integer.
Parameter name: x
Actual value was NaN.
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Yes   No  
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Due to two windows i am getting this error.
If i used only single window it works fine.
I am opening these windows in following way.

 

window.radopen(

"Page1.aspx","Radwindow1");

 

 

window.radopen("Page2.aspx","Radwindow2");


Thanks

Hello Shrirang,

I built up a test demo based on your code but unfortunately to no avail - I could not reproduce the problem you report. Would you please examine the attached test demo on your side and let me know what else should I do in order to reproduce the issue?

Regards,
Svetlina
the Telerik team