Maximizing a window with a WindowChromeBehavior.IgnoreTaskbarOnMaximize set to false makes it unusable

Hello,

I have some kind of issue with my custom window and WindowChromeBehavior. When not maximized, it runs fine and resizes fine, however, when maximized, a previously fixed problem appears again: The window gets stuck to the top left corner and is passing clicks through other windows. This only happens when IgnoreTaskbarOnMaximize is set to false. This does not happen with a normal window, only with my custom one. Here is a cut version of the template:

<ControlTemplate TargetType="{x:Type controls:ThemedWindow}">
    <Grid>
        <AdornerDecorator x:Name="Adorner">
            <Grid Background="{TemplateBinding Background}">
                <Grid.RowDefinitions>
                    <RowDefinition Height="20"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition Width="Auto"/>
                </Grid.ColumnDefinitions>
                <Grid x:Name="PART_MoveArea" Background="Transparent">
                    <Viewbox VerticalAlignment="Center" HorizontalAlignment="Left" Margin="10 1">
                        <TextBlock Text="{TemplateBinding Title}" />
                    </Viewbox>
                </Grid>
                <StackPanel Grid.Row="0" Grid.Column="1" Orientation="Horizontal">
                    <!-- Title bar buttons -->
                </StackPanel>
                <ContentPresenter Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="2" Margin="2"/>
            </Grid>
        </AdornerDecorator>
        <ResizeGrip x:Name="WindowResizeGrip"/>
        <!-- + usual props -->
        <Border BorderThickness="{TemplateBinding BorderThickness}"
                                BorderBrush="{TemplateBinding BorderBrush}" 
                                Background="{x:Null}"
                                HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
    </Grid>
    <!-- Triggers -->
</ControlTemplate>

And here is the WindowChromeBehavior:

new WindowChromeBehavior
{
    IgnoreTaskbarOnMaximize = false,
    ResizeBorderThickness = new Thickness(5),
    KeepBorderOnMaximize = true,                  
};

[jeuxjeux20]

You can find the source code here: https://github.com/TheMvvmGuys/FindMyGames/tree/ui-updates/FindMyGames/Controls

[batzen]

So i guess we should add some kind of guard to prevent such issues. @punker76 Should we add a check for WindowStyle = None in OnAttached and throw an exception if it’s not already set to None instead of setting it to None there?