Javascript error due to RadSpell

[Mir]

Recently I have upgraded Telerik version(UI for ASP.NET AJAX) of our project to 2016 Q1. I am using RadSpell on a modal window to check spelling of a textbox on a toolbar button click. After checking for spellings, when I am clicking Close button of the parent modal window, a javascript error is occurring. 

Unable to get property 'mouseup' of undefined or null reference
URL: http://localhost/iTrakWebApp/ScriptResource.axd?d=9q9IkYzT1P6H219_x_k_x6tLRP323yXAyrwkg1Ad2IPRcVJmSr5AfeHLfQpTT0ru3iT17DNdmYKU5PFr8hBs5AsWwk8jA0vEMVJJ-56Xnq_NSUL51QzqhcizV-kFio5lZ5xjPw2&t=ffffffffcf2f22b2

Note that, this error was not occurring in 2015 Q3 version. Also I can't reproduce the issue if I remove the RadSpell control from the page.

For convenience, I am adding the lines of code related to RadSpell control. It would be of great help if someone can point out why this js error is occurring. Thanks in advance.

 

<Rad:RadSpell ID="SpellCheck" runat="server" ButtonType="None" OnClientDialogClosed="SpellCheckClosed" IsClientID="true" meta:resourcekey="SpellCheckResource1" />

......

// called this function on spell check button click

function StartCheck() {
    var sources = [new Telerik.Web.UI.Spell.HtmlElementTextSource($get('<%=tbxSynopsis.ClientID %>'))];
    var spell = $find('<%= SpellCheck.ClientID %>');
    spell.set_textSource(new Telerik.Web.UI.Spell.MultipleHtmlElementsSource(sources));
    spell.startSpellCheck();
}

[Mir]

I forgot to mention another thing.

We are using the following meta tag.

<meta http-equiv="x-ua-compatible" content="IE=EmulateIE9"

But if we change this into 'IE=edge' the problem no longer occurs. But we can't render this in edge due to some other UI issues. So we have to render this in IE9 and also resolve this issue.

[Marin Bratanov]

Hello,

I am logging this for fixing and you can track its status here: http://feedback.telerik.com/Project/108/Feedback/Details/183819-radspell-throws-a-javascript-error-when-the-page-is-disposed. In the meantime I can suggest removing the DestroyOnClose property of the main RadWindow that holds your RadSpell instance, as this is the main thing that can trigger the page with the spell to be disposed. The good news is that this error is seen only when the page that holds the spell disposes and only if you have a debugger on so it should not interfere with your end users.

I have also updated your Telerik points for your report.

Regards,

Marin Bratanov
Telerik