The XamDockManager is in a grid in a UserControl (no other content in the grid.)  I have a couple of other similar controls (all instantiated through XAML, however) that are defined the same way and work fine.

Here's the XAML definition of the Dock Manager (sorry, I have no idea how to post formatted code here). More comments plus some code-behind will follow this:

<igDock:XamDockManager
    x:Name="UserRequestsDockManager"
    Theme="{Binding Path=Theme,
              RelativeSource={RelativeSource FindAncestor,
              AncestorType={x:Type local:UserRequestsControl}}}"
    PaneDragStarting="UserRequestsDockManager_PaneDragStarting"
    PaneNavigatorButtonDisplayMode="Never"
    >

    <!-- The document area - Holds User Request Details -->
    <igDock:DocumentContentHost>
        <igDock:SplitPane
            x:Name="UserRequestDocumentSplitPane"
            Visibility="Visible">
            <igDock:TabGroupPane
                x:Name="UserRequestDocumentTabGroupPane"
                Visibility="Visible"
                >
                <igDock:ContentPane
                    x:Name="UserRequestPane"
                    Tag="{Loc Dock_UserRequestDetails_PaneHeader}"
                    Header="{Loc Dock_UserRequestDetails_PaneHeader}"
                    Image="..\Images\icons\DockManager\descriptors_16x16.png"
                    HorizontalAlignment="Left"
                    VerticalAlignment="Top"
                    Visibility="Visible"
                    Closed="ContentPane_Closed"
                    >
                    <local:UserRequestsDetails
                        x:Name="UserRequestsWindow"
                        Visibility="Visible"
                        Width="{Binding ElementName=UserRequestPane, Path=ActualWidth}"
                        Height="{Binding ElementName=UserRequestPane, Path=ActualHeight}"
                        DataContext="{Binding RelativeSource={RelativeSource AncestorType={x:Type local:UserRequestsControl}, AncestorLevel=1}, Path=RequestInformation}"
                    />
                </igDock:ContentPane>
            </igDock:TabGroupPane>
        </igDock:SplitPane>
    </igDock:DocumentContentHost>

    <igDock:XamDockManager.Panes>
        <!-- Filter Pane, initially docked to the left
             This pane is declared first so that it
             takes up the full height. -->
        <igDock:SplitPane
            igDock:XamDockManager.InitialLocation="DockedLeft"
            x:Name="FilterSplitPane"
            >
            <igDock:ContentPane
                x:Name="UserRequestFilterPane"
                Closed="ContentPane_Closed"
                Header="{Loc UserRequestFilter_SearchFilter_Label}"
                Tag="{Loc UserRequestFilter_SearchFilter_Label}"
                >
                <local:UserRequestFilter
                    x:Name="UserRequestFilterWindow"
                    Theme="{Binding Path=Theme,
                              RelativeSource={RelativeSource FindAncestor,
                              AncestorType={x:Type local:UserRequestsControl}}}"
                    DomainId="{Binding Path=DomainId,
                              RelativeSource={RelativeSource FindAncestor,
                              AncestorType={x:Type local:UserRequestsControl}}}"
                    AppLanguage="{Binding Path=AppLanguage,
                              RelativeSource={RelativeSource FindAncestor,
                              AncestorType={x:Type local:UserRequestsControl}}}"
                    DataContext="{Binding RelativeSource={RelativeSource AncestorType={x:Type local:UserRequestsControl}, AncestorLevel=1}, Path=RequestSearchFilter}"
                    />
            </igDock:ContentPane>
        </igDock:SplitPane>
        <igDock:SplitPane
            x:Name="TopSplitPane"
            igDock:XamDockManager.InitialLocation="DockedTop"
            SplitterOrientation="Vertical"
            >
            <igDock:ContentPane
                igDock:SplitPane.RelativeSize="60,60"
                x:Name="UserRequestListPane"
                Image="..\Images\icons\DockManager\descriptorsearch_16x16.png"
                Tag="{Loc Dock_UserRequestList_PaneHeader}"
                Header="{Loc Dock_UserRequestList_PaneHeader}"
                CloseAction="HidePane"
                Closed="ContentPane_Closed"
                >
                <local:UserRequestsList
                    x:Name="UserRequestsListWindow"
                    DataContext="{Binding RelativeSource={RelativeSource AncestorType={x:Type local:UserRequestsControl}, AncestorLevel=1}, Path=RequestList}"
                    MinHeight="20"
                    AppLanguage="{Binding Path=AppLanguage,
                              RelativeSource={RelativeSource FindAncestor,
                              AncestorType={x:Type local:UserRequestsControl}}}"
                 />
            </igDock:ContentPane>
        </igDock:SplitPane>

        <!-- Bottom split pane - Holds User Request Events -->
        <igDock:SplitPane
            x:Name="UserRequestEventsSplitPane"
            igDock:XamDockManager.InitialLocation="DockedBottom"
            >
            <igDock:ContentPane
                x:Name="UserRequestEventsPane"
                Image="..\Images\icons\DockManager\itemdetails_active_16x16.png"
                Tag="{Loc Dock_UserRequestEvents_PaneHeader}"
                Header="{Loc Dock_UserRequestEvents_PaneHeader}"
                Closed="ContentPane_Closed"
                >
                <local:UserRequestEvents
                    x:Name="UserRequestEventsWindow"
                    MinHeight="20"
                    DataContext="{Binding RelativeSource={RelativeSource AncestorType={x:Type local:UserRequestsControl}, AncestorLevel=1}, Path=RequestInformation}"
                >
                </local:UserRequestEvents>
            </igDock:ContentPane>
        </igDock:SplitPane>
    </igDock:XamDockManager.Panes>
</igDock:XamDockManager>

The "UserRequestDetails" control is the one not showing up - or I should say, that shows up only when it feels like it.

Here's how I instantiate it in code-behind (I'm sure there's a better way to do this, but could not find anything, so this "works" for now:)

                _rulingRequests = New UserRequestsControl(UserRequestsControl.RequestType.Ruling)

                Dim _themeBinding As Binding = New Binding("Theme")
                _themeBinding.ElementName = "CCSWPFRibbon"
                BindingOperations.SetBinding(_rulingRequests, UserRequestsControl.ThemeProperty, _themeBinding)

                Dim _layoutLockedBinding As Binding = New Binding("IsLayoutLocked")
                _layoutLockedBinding.ElementName = "CCSMainWindow"
                BindingOperations.SetBinding(_rulingRequests, UserRequestsControl.IsLayoutLockedProperty, _layoutLockedBinding)

                Dim _appLanguageBinding As Binding = New Binding("ApplicationLanguage")
                _appLanguageBinding.Source = Application.Current
                BindingOperations.SetBinding(_rulingRequests, UserRequestsControl.AppLanguageProperty, _appLanguageBinding)

                'Dim _domainIdBinding As Binding = New Binding("DomainId")
                '_domainIdBinding.ElementName = "CCSMainWindow"
                'BindingOperations.SetBinding(_rulingRequests, UserRequestsControl.DomainIdProperty, _domainIdBinding)

                MainWindowGrid.Children.Add(_rulingRequests)

"MainWindowGrid" is a grid in the main window (right... :)) which contains two rows: The first has a XamRibbon, the second has whatever user control is "current" (the other ones are collapsed.)  I set Grid.Row="1" in the XAML for the user control, so it appears in the right place - it's just the document (UserRequestDetail) that doesn't show up.  As I mentioned in the other post, I don't think UserRequestDetail is the problem, since even a simple control with only a textbox in it exhibits the same behaviour.

I tried adding a call to ApplyTemplate at the end of the code-behind code, no luck (though there was some false hope for a couple of minutes.)  Maybe that should go elsewhere (if it's in any way related.)

This is seriously bugging me since this new functionality is due in about two weeks from now.

Thanks,
Michel