WPF：两个TabControls /切换在Win7 / .NET 4.5下工作，但在Windows 8.1 / .NET 4.5.1下不工作

Question

I've got a window with two TabControls. One is Left-Aligned, the other right-aligned. The Headers of the TabControls are aligned in the top row.

Whenever I click a TabItem, the other TabControl is unfocused.

That works perfectly fine on my development PC (Windows 7, .NET Framework 4.5).

However, when I execute it under a PC with Windows 8.1 (.NET 4.5.1), I can not switch to the right-aligned TabControl. When I click on a TabItem inside it, nothing at all happens.

XAML of the MainWindow:

    <Window x:Class="TabGroupProblem.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded">
        <Grid>
            <TabControl GotFocus="TabControl_GotFocus" x:Name="c1">
                <TabItem Header="One">h</TabItem>
                <TabItem Header="Two">i</TabItem>
            </TabControl>

            <TabControl GotFocus="TabControl_GotFocus_1" x:Name="c2">
                <TabControl.Resources>
                    <Style TargetType="{x:Type TabPanel}">
                        <Setter Property="HorizontalAlignment" Value="Right" />
                    </Style>
                </TabControl.Resources>
                <TabItem Header="Three">j</TabItem>
                <TabItem Header="four">k</TabItem>
            </TabControl>
        </Grid>
    </Window>

Event Handlers:

    private void TabControl_GotFocus(object sender, RoutedEventArgs e)
    {
        // c1 to foreground
        System.Windows.Controls.Grid.SetZIndex(c2, -1);
        c2.SelectedIndex = -1;
    }

    private void TabControl_GotFocus_1(object sender, RoutedEventArgs e)
    {
        // c2 to foreground
        System.Windows.Controls.Grid.SetZIndex(c2, 1);
        c1.SelectedIndex = -1;
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        System.Windows.Controls.Grid.SetZIndex(c1, 0);
        System.Windows.Controls.Grid.SetZIndex(c2, -1);
        c2.SelectedIndex = -1;
    }

Why does that happen, and what can I do against it?

edit: Switched the Target framework to .NET 4.5.1 on my development PC. Switching between TabControls still works on my PC (and still not on the Windows 8.1 PC)

Answer 1

You are placing two TabControls directly over each other, but still expect to be able to focus the one underneath. This obviously happens to work in Win7, but it would appear Windows 8 uses a different control template that potentially eats the mouse clicks on the "blank" bit of the TabPanel.

Maybe it's adding a transparent brush, so you could try a simple:

<TabControl.Resources>
    <Style TargetType="{x:Type TabPanel}">
        <Setter Property="Background" Value="{x:Null}" />
    </Style>
</TabControl.Resources>

However, I suspect it would be easier to ditch the tab control and just create some styled buttons yourself?