[Solved] Popup appears behind PDF iframe

[Gary]

Hi,

I've got a popup created using WindowBuilder in MVC:

@{ Html.Telerik().Window()
        .Name("Window")
        .Title(ViewData["errorTitle"] == null ? "Messages" : ViewData["errorTitle"].ToString())
        .Draggable(true)
        .Resizable(resizing => resizing
            .Enabled(true)
            .MinWidth(250)
            .MaxHeight(500)
            .MaxWidth(500)
        )
        .HtmlAttributes(new {style = "top: 0px; left: 0px; z-index:1000"})
        .Visible(false)
        .Modal(true)
        .Buttons(b => b.Close())
        .Content(@<text>
        <div style="width: 100%;">
            <p>
                @if (ViewData["error"] != null)
                {
                    @Html.Raw(HttpUtility.HtmlDecode(ViewData["error"].ToString()))
                }
            </p>
            <div style="text-align: center; padding-top: 20px">
                <input type="button" class="btn" value="OK" style="width: 100px" onclick="javascript:$('#Window').data('tWindow').close();" />
            </div>
        </div>
        </text>)
        .Width(450)

        .Render();
    }

The problem is the popup hides under an iframe that has a PDF file as its source. This only happens in IE (I'm using IE 9 32-bit). Firefox and Chrome don't have this problem. As you can see in the code, I've tried setting its z-index to a really high number, to no avail.

Any help is appreciated.