Recent Windows IE Security update appears to break the HTMLPlaceHolder when used with an ActiveX control

3 posts, 0 answers
  1. Andrew
    Andrew avatar
    104 posts
    Member since:
    May 2008

    Posted 16 Apr 2013 Link to this post

    I have a RadTabControl that has two tabs. The first contains a RadGridView, the second a RadHTMLPlaceHolder that directs to a page with an ActiveX control. If you switch to the tab with the HTMLPlaceHolder, the page loads, but if you switch back to the first tab the ActiveX control never hides and continues to float above the RadGridView. This used to work on both Windows 7 and 8 before installing this update , and works again when uninstalling said update. My guess is that it probably specifically relates to this article: which reads:

    "Contents of an iFrame are not hidden when a Div's display style is set to "none" in Internet Explorer 10 in Windows 7 and Windows 8"

    which seems to claim to fix the exact problem that is now occurring. Is it possible that you guys had a workaround for this issue that is now broken due to this fix from Microsoft?

    We've had a ton of reports come in from customers since last Wednesday reporting this issue. Any help would be appreciated.


  2. Andrew
    Andrew avatar
    104 posts
    Member since:
    May 2008

    Posted 18 Apr 2013 Link to this post

    My current workaround for this issue is to call ajavascript function on the page our silverlight app is sitting on:

    function CloseIFrameContent(shouldClose, frameName) {
        var window = document.getElementById(frameName).contentWindow;
        if (window != null) {
            var doc = window.document;
            if (doc != null && doc.body != null) {
                if (shouldClose) {
           = "none";
                } else {
           = "block";

    This is called from silverlight in the RadTabControl's SelectionChanged event. It hides or shows the content of the IFrame. Obviously this solution will only work if the main page and iFrame are hosted on the same domain, otherwise you'd end up with XSS errors.
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  4. Pavel R. Pavlov
    Pavel R. Pavlov avatar
    1167 posts

    Posted 19 Apr 2013 Link to this post

    Hi Andrew,

    For best performance we recommend integrating the RadHtmlPlaceholder with our RadWindow control. For more information you can refer to this article.

    Furthermore, you can subscribe to the SelectionChanged event of the RadTabControl and check the selected tab and show/hide the RadWindow accordingly. You can implement this approach like this:

    public MainPage()
        w = new RadWindow();
        RadHtmlPlaceholder p = new RadHtmlPlaceholder();
        p.SourceUrl = new Uri("", UriKind.Absolute);
        w.Content = p;
    RadWindow w;
    private void xTab_SelectionChanged(object sender, RadSelectionChangedEventArgs e)
        if ((e.AddedItems[0] as RadTabItem).Header.ToString() == "MyTabName_1")

    Pavel R. Pavlov
    the Telerik team

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