Andrew,

I did a small sample with your suggestion but it's not working. Below is the code and output.

Notice the last 2 cases where :

Keyboard.FocusedElement - System.Windows.Controls.Button: Activate and Deactivate Pane

but

Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane

 Am I missing something else ?

Thanks,
Claudio.

----------CODE STARTS---------

XAML

<Window x:Class="DeactivatePane.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:igDock="http://infragistics.com/DockManager"
    Title="Window1" Name="win" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="50"/>           
        </Grid.RowDefinitions>
        <igDock:XamDockManager x:Name="dockManager" Grid.Row="0" >
            <igDock:XamDockManager.Panes>
                <igDock:SplitPane>
                    <igDock:ContentPane x:Name="contentPane" Header="Right Edge Dock Pane">
                        <TextBox>Content Pane</TextBox>
                    </igDock:ContentPane>
                </igDock:SplitPane>
            </igDock:XamDockManager.Panes>
        </igDock:XamDockManager>
        <Button Name="btnActivateAndDeactivate" Content="Activate and Deactivate Pane" Grid.Row="1" Click="btnActivateDeactivate_Click" ></Button>
    </Grid>
</Window>

C#:

    private void btnActivateDeactivate_Click(object sender, RoutedEventArgs e)
        {           
            Console.WriteLine("\n\nActivating Pane");
            contentPane.Activate();
            DisplayActivePane();
            Console.WriteLine("\n\nTrying to Deactivate Pane - Focus on Window (via Focus() method)");           
            win.Focus();
            DisplayActivePane();
            Console.WriteLine("\n\nTrying to Deactivate Pane - Focus on Window (via Keyboard)");
            Keyboard.Focus(win);
            DisplayActivePane();
            Console.WriteLine("\n\nTrying to Deactivate Pane - MoveFocus() method");
            contentPane.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
            DisplayActivePane();
            Console.WriteLine("\n\nTrying to Deactivate Pane - Focus on Button (via Focus() method)");
            btnActivateAndDeactivate.Focus();
            DisplayActivePane();
            Console.WriteLine("\n\nTrying to Deactivate Pane - Focus on Button (via Keyboard)");
            Keyboard.Focus(btnActivateAndDeactivate);
            DisplayActivePane();

        }


        private void DisplayActivePane()
        {
            Console.WriteLine("Keyboard.FocusedElement - " + Keyboard.FocusedElement);
            Console.WriteLine("Current Active Pane - "  +dockManager.ActivePane);
        }

----------CODE ENDS---------

----------OUTPUT START---------

Activating Pane
Keyboard.FocusedElement - System.Windows.Controls.TextBox: Content Pane
Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane


Trying to Deactivate Pane - Focus on Window (via Focus() method)
Keyboard.FocusedElement - System.Windows.Controls.TextBox: Content Pane
Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane


Trying to Deactivate Pane - Focus on Window (via Keyboard)
Keyboard.FocusedElement - System.Windows.Controls.TextBox: Content Pane
Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane


Trying to Deactivate Pane - MoveFocus() method
Keyboard.FocusedElement - System.Windows.Controls.TextBox: Content Pane
Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane


Trying to Deactivate Pane - Focus on Button (via Focus() method)
Keyboard.FocusedElement - System.Windows.Controls.Button: Activate and Deactivate Pane
Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane


Trying to Deactivate Pane - Focus on Button (via Keyboard)
Keyboard.FocusedElement - System.Windows.Controls.Button: Activate and Deactivate Pane
Current Active Pane - Infragistics.Windows.DockManager.ContentPane Header:Right Edge Dock Pane Content:Content Pane
 

----------OUTPUT ENDS---------

Sorry I didn't mean to imply its a synchronous change - just that it is based upon the focused element. We delay changing the active pane in case focus is shifting from one pane to another or focus is leaving the pane only to come back into the pane because its being moved from floating to docked or vice versa. If we didn't delay then you would get a lot of unneeded ActivePaneChanged events and changes to the ActivePane. The ActivePaneChanged event will be invoked once the activepane has been changed.