Using 2009.1, WebDialogWIndow inside an UpdatePanel.

In FF 3.0 but not in IE7 I see this problem.

I have a non-modal window defined as follows:

    <ig:WebDialogWindow ID="winExerSelect" CssClass="NonModalWindow"  runat="server"
        Height="478px" Width="284px" MaintainLocationOnScroll="false"  InitialLocation="Manual"
        BorderStyle="Solid" BorderWidth="1px" StyleSetName="RubberBlack" WindowState="Minimized"
        Left="634px">
        <Header CaptionText="Select Exercises" CaptionAlignment="Left" MinimizedWidth="284" Height="26px" >
            <CloseBox Visible="false" />
            <MaximizeBox Visible="false" />
            <MinimizeBox Visible="true" />
        </Header>
        <ContentPane>
            <Template >
                <exer:selector id="wucExerciseSelect" runat="server"  OnExerciseSelected="wucExerciseSelect_ExerciseSelected" />
            </Template>
        </ContentPane>
    </ig:WebDialogWindow>

under certain conditions I am seeing the LEFT property of the rendered DIV growing every time the UpdatePanel is refreshed.  It depends on the height of the browser wiwndow.  if it is above a certain height, LEFT does not grow.  If the window is short enough that a vertical scroll bar is rendered,LEFT does not grow.  However in between those 2 values - short enough but not too short - the LEFT property on the rendered DIV increases by 16px every time the UpdatePanel refreshes.

Anyone have any ideas?

All I really need is to specify an initial location for the WDW, after that it is up to the user of the page to position the window, I just want it to stay where they put it.