WPF Focus, can't get both logical and keyboard focus

Question

I have been through several other postings about WPF and focus, and the best I can figure there's something I'm missing in my code. I'm working on an app using strict MVVM so I'm trying to avoid any code-behind in the view files (using attached behaviors when code-behind is necessary), but at this point even putting the focus code in the code-behind of the view it's not working.

I have an application with a main window and I'm trying to make a search window popup on a hot key. I'd like as soon as the user hits the hot key, the keyboard focus to be on the search text so it's just hotkey and then type your search term. Everything but the logical focus is working at this point, even though keyboard claims to have focus on the element.

I can't seem to get it to take both keyboard and logical focus at the same time from the code. However, if I hit Tab as soon as the search box appears, I'm put right into the text box.

Main window code:

<ribbon:RibbonWindow x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:ribbon="clr-namespace:Microsoft.Windows.Controls.Ribbon;assembly=RibbonControlsLibrary"
    xmlns:attached="clr-namespace:UserInterface.Attached"
    xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:command="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF45"
    xmlns:viewModels="clr-namespace:UserInterface.ViewModels"
    xmlns:views="clr-namespace:UserInterface.Views"
    xmlns:layout="clr-namespace:UserInterface.ViewModels.Layout"
    xmlns:layout1="clr-namespace:UserInterface.Views.Layout"
    MinHeight="560"
    MinWidth="950"
    WindowStartupLocation="CenterScreen" 
    Icon="{Binding Layout.IconPath}"
    DataContext="{Binding Main, Source={StaticResource Locator}}"
    FocusManager.FocusedElement="{Binding ElementName=LayoutControl}"
    Title="{Binding Layout.Title}">

<!-- Ribbon menu shortcuts  -->
<Window.InputBindings>
    <KeyBinding Modifiers="Control" Key="T" Command="{Binding Layout.Commands[GlobalObjectSearch]}" />
</Window.InputBindings>

<Grid>
    <ContentPresenter Content="{Binding Layout}" x:Name="LayoutControl">
        <ContentPresenter.Resources>
            <DataTemplate DataType="{x:Type layout:MainViewModel}">
                <layout1:MainView/>
            </DataTemplate>
        </ContentPresenter.Resources>
    </ContentPresenter>
</Grid>
</ribbon:RibbonWindow>

Code to make search window appear:

    public SelfClosingDialogView ShowSelfClosingDialog(IWindowDialogViewModel dataContext)
    {
        dataContext.CheckWhetherArgumentIsNull(nameof(dataContext));

        var view = new SelfClosingDialogView
        {
            DataContext = dataContext,
            Owner = Application.Current?.MainWindow
        };

        view.Show();

        return view;
    }

Search window code (Reused, so generic):

<Window x:Class="UserInterface.Views.DialogViews.SelfClosingDialogView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:attached="clr-namespace:UserInterface.Attached"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
    mc:Ignorable="d"
    SizeToContent="WidthAndHeight"
    WindowStyle="None"
    WindowStartupLocation="CenterOwner">

<!-- Allow view models to cause the window to close -->
<Window.Style>
    <Style TargetType="{x:Type Window}">
        <Style.Triggers>
            <DataTrigger Binding="{Binding IsClosed}" Value="true">
                <!-- Executes close -->
                <Setter Property="attached:WindowCloseBehavior.Close" Value="true" />
            </DataTrigger>
        </Style.Triggers>
    </Style>
</Window.Style>

<!-- Displays the passed-in view model -->
<Grid>
    <ContentPresenter x:Name="DialogPresenter" Content="{Binding}" Margin="0" />
</Grid>
</Window>

Code for my search view:

<UserControl x:Class="UserInterface.Views.DialogViews.ObjectSearchView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:dialogViewModels="clr-namespace:UserInterface.ViewModels.DialogViewModels"
         xmlns:utils="clr-namespace:WPF.Utils"
         xmlns:attached="clr-namespace:UserInterface.Attached"
         mc:Ignorable="d"
         d:DataContext="{d:DesignInstance dialogViewModels:ObjectSearchViewModel}"
         MinWidth="250"
         Focusable="True"
         FocusManager.IsFocusScope="True">
<UserControl.InputBindings>
    <KeyBinding Key="Enter" Command="{Binding BrowseToObjectCommand}" />
    <KeyBinding Key="Escape" Command="{Binding CloseWindowCommand}" />
</UserControl.InputBindings>
<UserControl.Resources>
    <Style BasedOn="{StaticResource FormTextBlockStyle}" TargetType="TextBlock" />
</UserControl.Resources>

<StackPanel>
    <TextBox Name="SearchText" 
             Focusable="True"
             Text="{utils:ValidatingLiveBinding SearchText}" 
             attached:NavigatingListBoxBehavior.LinkedListBox="{Binding ElementName=SearchResults}">
    </TextBox>
    <ScrollViewer HorizontalScrollBarVisibility="Hidden"
                  VerticalScrollBarVisibility="Auto"
                  MaxHeight="400">
        <ListBox Name="SearchResults"
                 ItemsSource="{Binding SearchResults}" 
                 SelectedItem="{Binding SelectedSearchItem}" 
                 Visibility="{Binding HasSearchResults, Converter={StaticResource BooleanToVisibilityConverter}}"
                 attached:ItemsControlProperties.DoubleClickCommand="{Binding BrowseToObjectCommand}"
                 KeyboardNavigation.IsTabStop="False"
                 IsSynchronizedWithCurrentItem="True" />
    </ScrollViewer>
</StackPanel>
</UserControl>

And finally, the code-behind hack I'm trying to attempt to get focus (plus debugging code so that I don't lose the focus switching back and forth to Visual Studio):

public partial class ObjectSearchView : UserControl
{
    public ObjectSearchView()
    {
        InitializeComponent();
        this.Loaded += this.OnLoad;
    }

    private void OnLoad(object sender, RoutedEventArgs e)
    {
        this.PrintFocusInfo();
        FocusManager.SetFocusedElement(FocusManager.GetFocusScope(this), this.SearchText);
        this.PrintFocusInfo();
        this.SearchText.Focus();
        this.PrintFocusInfo();
        Keyboard.Focus(this.SearchText);
        this.PrintFocusInfo();
    }

    [Conditional("DEBUG")]
    private void PrintFocusInfo()
    {
        var logicalElement = FocusManager.GetFocusedElement(FocusManager.GetFocusScope(this.SearchText));
        Debug.WriteLine("Current logical focus is on '{0}', of type '{1}' ({2})".FormatInvariantCulture((logicalElement as FrameworkElement)?.Name, logicalElement?.GetType().Name, logicalElement));
        var focusedElement = Keyboard.FocusedElement;
        Debug.WriteLine(
            "Current Keyboard Focus is on '{0}', of type '{1}' ({2})".FormatInvariantCulture(
                (focusedElement as FrameworkElement)?.Name,
                focusedElement.GetType().Name,
                focusedElement));
    }
}

Output window contents:

Current logical focus is on '', of type '' ()
Current Keyboard Focus is on '', of type 'MainWindow' (UserInterface.Views.MainWindow)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on '', of type 'MainWindow' (UserInterface.Views.MainWindow)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on 'SearchText', of type 'TextBox' (System.Windows.Controls.TextBox)
Current logical focus is on '', of type '' ()
Current Keyboard Focus is on 'SearchText', of type 'TextBox' (System.Windows.Controls.TextBox)

I've tried to include everything I can think of, but I cannot get logical focus to show anything except null.

Answer 1

Here is the behavior I ultimately created which fixed this for me. There's still a lot I don't know about WHY this works... but if you're having a problem getting Focus to cooperate it looks like the key is catching it when IsVisible is set to true, and having the Dispatcher set the focus for you. I linked this event to the IsVisibleChanged element on the textbox (through an attached behavior).

    private void SetFocusOnVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
    {
        if ((bool)e.NewValue)
        {
            this.Dispatcher.BeginInvoke(DispatcherPriority.ContextIdle, new Action(() => this.AssociatedObject.Focus()));
        }
    }