I made a simple code to describe my curious but problematic situation.

I the XAML i have a window with a grid containing only the XamDockManger control, with a SplitPane on the bottom and a DocumentContentHost, that only contains a TreeView.

XAML

     <Grid>
        <igDock:XamDockManager Name="xamDockManager1">

            <igDock:XamDockManager.Panes>

                <igDock:SplitPane igDock:XamDockManager.InitialLocation="DockedBottom" x:Name="splitPane" SplitterOrientation="Horizontal">
                    <igDock:ContentPane IsPinned="False" x:Name="contentPane" Header="sads">
                        <TextBox x:Name="tb1"></TextBox>
                    </igDock:ContentPane>
                </igDock:SplitPane>

            </igDock:XamDockManager.Panes>

            <igDock:DocumentContentHost x:Name="centralProcContainer">
                <igDock:SplitPane>
                    <igDock:TabGroupPane>
                        <igDock:ContentPane>
                                <TreeView SelectedItemChanged="TreeView_SelectedItemChanged">
                                <TreeViewItem Header="1"></TreeViewItem>
                                <TreeViewItem Header="2">
                                    <TreeViewItem Header="4">
                                        <TreeViewItem Header="5"></TreeViewItem>
                                        <TreeViewItem Header="6"></TreeViewItem>
                                    </TreeViewItem>
                                </TreeViewItem>
                                <TreeViewItem Header="3"></TreeViewItem>
                            </TreeView>
                        </igDock:ContentPane>
                    </igDock:TabGroupPane>
                </igDock:SplitPane>
            </igDock:DocumentContentHost>
        </igDock:XamDockManager>
    </Grid>

Now in the c# code i have the event

CODE

         private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
        {
            contentPane.Activate();
        }

Objective

The goal is to open the bottom split pane everytime you select a different item on tree view, and it works fine for the first nodes, but try to expand the treeview with the header 4, or 5 or 6 and select them, when the contentPane is activated i don't know how but the first node of the treeView of that branch is selected in last.

If anyone can tell me why this nodes 4,5 and 6 can't be selected and if there is a workaround i appreciate.

Best regards,
João Loureiro