Wrong behavior with ShowTitleBar="False" in XAML control metrowindow settings

[whentotrade]

Setting ShowTitleBar to "False" in the controls metrowindow xaml results in the still shown title bar in the window. The dynamic binding in the demo works, but if it is set to "false" in the xaml control definition, the title bar is still there.

What steps will reproduce this issue?

You can check by replacing the MahApps.Metro.Demo.NET45

from

<Controls:MetroWindow x:Class="MetroDemo.MainWindow"
                    ....
                      ShowTitleBar="ShowTitleBar="{Binding ShowMyTitleBar, Mode=OneWay}"

to

<Controls:MetroWindow x:Class="MetroDemo.MainWindow"
                    ....
                      ShowTitleBar="False"

Expected outcome

TitleBar should be hidden when set to False in XAML definition.

Environment

• MahApps.Metro v1.6
• Windows OS 10
• Visual Studio 2017
• .NET Framework 4.61

[Pekshev]

I did a demo project and bound ShowTitleBar to the ViewModel property. As in your demo project. However, it also does not work - the titlebar does not collapse, but hides

<mah:MetroWindow x:Class="WpfApp3.MainWindow"
                 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:local="clr-namespace:WpfApp3"
                 xmlns:mah="http://metro.mahapps.com/winfx/xaml/controls"
                 mc:Ignorable="d" SaveWindowPosition="True"
                 Height="250" Width="525"
                 ShowTitleBar="{Binding Path=ShowTitleBar, Mode=OneWay}" 
                 Loaded="MainWindow_OnLoaded">
    <Window.Resources>
        <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Fonts.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Colors.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/Blue.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Accents/BaseLight.xaml" />
            <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/FlatSlider.xaml"/>
        </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>
    <Window.DataContext>
        <local:ViewModel></local:ViewModel>
    </Window.DataContext>
    <Grid>
        <TextBlock FontSize="16" Text="MY TITLE" 
                   PreviewMouseLeftButtonDown="UIElement_OnPreviewMouseLeftButtonDown"></TextBlock>
        <CheckBox Content="show title bar" IsChecked="{Binding Path=ShowTitleBar, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                  HorizontalAlignment="Center" VerticalAlignment="Bottom" Margin="5"></CheckBox>
        <Button VerticalAlignment="Center" HorizontalAlignment="Center"
                Content="Show child window" Click="ButtonBase_OnClick"></Button>
    </Grid>
</mah:MetroWindow>

ViewModel:

using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace WpfApp3
{
    public class ViewModel : INotifyPropertyChanged
    {
        private bool _showTitleBar = true;
        public bool ShowTitleBar
        {
            get => _showTitleBar;
            set
            {
                _showTitleBar = value;
                OnPropertyChanged();
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

[punker76]

@whentotrade @Pekshev I'm working on this...

[Pekshev]

Suddenly it will help: in your demo project, if you first use item Toggle Fillscreen (no taskbar, window style = none), then the titlebar also stops disabling

[WojciechNagorski]

There is a workaround?

[davikor]

Maybe #3212 is related

Really need to see a fix and a NuGet release for this issue, it's quite annoying for apps which relies on ShowTitleBar

[batzen]

@bbougot This is open source. If you need a fix ASAP, fix it yourself and create a pull request.

@batzen Am I supposed to know how to fix it?

[batzen]

@bbougot Is anyone supposed to fix it for you if you need it ASAP?

@batzen No, I am only highlighting this is a very handicapping issue and, regarding the impacted users and the fact it has been living for a long time (release > 1.5), it should be considered as highly prioritized. No more, no less.