competent, please review the new sample I have attached and let me know if this helps.  I made a few property changes on the XamDialog Window, including setting IsModal to False.  I think this works better as False because the ChildWindow itself is a modal dialog.  I also set the WindowState to Hidden and removed the Visibility setting.

I have also implemented the dialog as a separate user control.  I am not seeing the exception as you are.  Please test out this sampe and let me know if this helps.

Thanks,
Francis

Hello,

I created a sample SL4 application (in C#) based on your code snippets.  I believe it demonstates the first issue you mention; the WebDialogWindow displayed outsdie the Child Window (File Uploader). 

One thing I'm a bit puzzled by is why the dialog window is visible intially upon showing the Child Window that contains it.  I was expecting it to be collapsed based on the setting in xaml.

I will forward this sample onto our engineers for their review.  Feel free to modify the sample and re-attach, if you feel any changes are needed.

Thanks,
Francis

There is also a secondary, probably related issue with this configuration: I added the xamDialogWindow to a usercontrol so that we could leverage its functionality in multiple windows, but now the control is throwing the following exception after the user control is loaded into the page (the xamDialogWindow does not have to be loaded for this exception to be thrown):

Message: Unhandled Error in Silverlight Application
) General Information
*********************************************
TimeStamp: 10/17/2010 4:27:17 PM
Assembly: UITest
AppDomainName: Silverlight AppDomain

1) Exception Information
*********************************************
Exception Type: System.ArgumentException
Message: Value does not fall within the expected range.

StackTrace Information
*********************************************
   at MS.Internal.XcpImports.MethodEx(IntPtr ptr, String name, CValue[] cvData)
   at MS.Internal.XcpImports.MethodPack(IntPtr objectPtr, String methodName, Object[] rawData)
   at MS.Internal.XcpImports.UIElement_TransformToVisual(UIElement element, UIElement visual)
   at Infragistics.Controls.Interactions.XamDialogWindow.GetContainerPanelCoords(FrameworkElement container)
   at Infragistics.Controls.Interactions.XamDialogWindow.CenterDialogWindow()
   at Infragistics.Controls.Interactions.XamDialogWindow.XamWebDialogWindow_LayoutUpdated(Object sender, EventArgs e)
   at System.Windows.FrameworkElement.OnLayoutUpdated(Object sender, EventArgs e)
   at MS.Internal.JoltHelper.RaiseEvent(IntPtr target, UInt32 eventId, IntPtr coreEventArgs, UInt32 eventArgsTypeIndex)   at MS.Internal.XcpImports.MethodEx(IntPtr ptr, String name, CValue[] cvData)
   at MS.Internal.XcpImports.MethodPack(IntPtr objectPtr, String methodName, Object[] rawData)
   at MS.Internal.XcpImports.UIElement_TransformToVisual(UIElement element, UIElement visual)
   at Infragistics.Controls.Interactions.XamDialogWindow.GetContainerPanelCoords(FrameworkElement container)
   at Infragistics.Controls.Interactions.XamDialogWindow.CenterDialogWindow()
   at Infragistics.Controls.Interactions.XamDialogWindow.XamWebDialogWindow_LayoutUpdated(Object sender, EventArgs e)
   at System.Windows.FrameworkElement.OnLayoutUpdated(Object sender, EventArgs e)
   at MS.Internal.JoltHelper.RaiseEvent(IntPtr target, UInt32 eventId, IntPtr coreEventArgs, UInt32 eventArgsTypeIndex)
Line: 1
Char: 1
Code: 0

Sorry, I should have been more specific about the situation. The ChildWindow is in a separate xaml page that is opened in code in response to a user action (the ChildWindow is shared among multiple controls which is why it is not defined in xaml). The code creates a new instance of the ChildWindow and then calls its Show method:

            Dim oWindow As New FileUploader
 
            oWindow.Show()

The xamDialogWindow is defined in xaml on the ChildWindow control. The RestrictInContainer was already set.

                    <ig:XamDialogWindow Name="dlgProgress" Header="Uploading Files" Width="400" Height="124" Grid.RowSpan="2" IsModal="True" HeaderIconVisibility="Collapsed" StartupPosition="Manual" Visibility="Collapsed" VerticalAlignment="Center" HorizontalAlignment="Center" RestrictInContainer="True" IsResizable="False" IsTabStop="False" MaximizeButtonVisibility="Collapsed" MinimizeButtonVisibility="Collapsed" CloseButtonVisibility="Collapsed">
                        <StackPanel Margin="4">
                            <TextBlock Text="{Binding FileName}" Margin="0,6,0,10" />
                            <ProgressBar Height="15" Value="{Binding PercentCompleted}"  />
                            <Button Content="Cancel" HorizontalAlignment="Center" Margin="0,10,0,0" Click="cmdCancelUpload_Click" />
                            <TextBlock Text="" Width="400" />
                        </StackPanel>
                    </ig:XamDialogWindow>

The dialog is shown in response to a user action:

        dlgProgress.Show()