Slow closing RadWindow Lightweight rendering in Internet Explorer

[Eric]

Guys, 

I am facing a performance issue when closing a radwindow Lightweight rendering in only IE browser (IE v11).

I tried hiding the radwindow by using onClientBeforeClose client event to improve user experience BUT I got no lucky. The problem is still the same.

Is there any way which can solve it or improve UX when closing the radwindow?

function OnClientBeforeCloseHandler(sender, args) {
    if (sender && sender.get_popupElement() && sender.get_popupElement().style && $telerik.isIE) {
        sender.get_popupElement().style.display = "none";
    }
}

[Marin Bratanov]

Hello Eric,

This is not a known issue and apart from the idea you've already tried, I can suggest a few others:

• try using setUrl("about:blank") in the OnClientBeforeClose handler
• ensure IE is running in Edge mode (i.e., standards mode) and not in Compatibility mode or in IE10 mode. This can also be enforced with a <meta> tag and/or an HTTP header
• review whether there is any additional code running (e.g., an AJAX request initiated by the OnClientClose handler, or by the code that called the RadWindow's close() method)
• if a server request is closing the dialog, ensure you are using the Sys.Application.Load event to close the RadWindow, in a fashion similar to the approach used here
• try setting the DestroyOnClose property to true in case the issue stems from the content page (test with a different, simple one to confirm) and the fact that closing the RadWindow merely hides it with CSS

If neither helps, I advise that you open a support ticket and send us a small runnable example so we can investigate. 

Regards,

Marin Bratanov
Telerik by Progress