WPF Modal window not rendering title area on initial ShowDialog() until mouse move

Question

WPF Modal window not rendering title area on initial ShowDialog() until mouse move

Chris 0

I'm using .NET Framework6.0 and encountering a strange render issue in a custom WPF modal dialog.

Environment:

.NET FrameWork4.6
Windows: Windows 11 64-bit

When I display a window using ShowDialog() in a button click event and the title are doesn't render on initial display, the only occurs occasionally and can't be reliably reproduced.

The phenomenon is as follows:

normal show:

User's image

abnormal show:

User's image

My UI is as follows. I set property via back code.

<Window x:Class="MessageboxDispalyTesting.TransparentDialog"

    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:MessageboxDispalyTesting"

    mc:Ignorable="d"

    WindowStyle="None"

    SizeToContent="WidthAndHeight"

    ResizeMode="NoResize"

    ShowInTaskbar="False"

    Topmost="False"

    Title="TransparentDialog" 

    WindowStartupLocation="CenterScreen"

    AllowsTransparency="True"

    Background="Transparent"

    Height="300" Width="300">

<Border x:Name="GMB_Border" >

    <Grid>

        <Grid.RowDefinitions>

            <RowDefinition Height="auto" />

            <RowDefinition Height="*" />

            <RowDefinition Height="auto"/>

        </Grid.RowDefinitions>

        <Grid x:Name="GMB_Title" Height="40">

            <Grid.ColumnDefinitions>

                <ColumnDefinition Width="auto" />

                <ColumnDefinition Width="*" />

                <ColumnDefinition Width="30" />

                <ColumnDefinition Width="auto" />

            </Grid.ColumnDefinitions>

            <Image x:Name="GIMG_Title" Width="60" Height="60" Margin="-10,0,-10,-10"/>

            <Grid Grid.Column="1" Margin="5,0,0,0"  >

                <TextBlock x:Name="GTXT_Title" HorizontalAlignment="Left" VerticalAlignment="Center" />

                <Rectangle x:Name="GRT_Line" Fill="White" HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Height="2" Visibility="Collapsed" Margin="0,0,-25,2"/>

            </Grid>

            <Image x:Name="GIMG_Title2" Grid.Column="3" Width="40" Height="70" Margin="0,5,5,0" Visibility="Collapsed"/>

            <Button x:Name="GMB_Close"  Grid.Column="3" Margin="5" Padding="4"  />

        </Grid>

        <AdornerDecorator Grid.Row="1">

            <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">

                <StackPanel x:Name="GMB_ContentPanel" Orientation="Vertical" Margin="10,8,60,10">

                    <Grid x:Name="GMB_Module" 

                            TextBlock.FontSize="15" TextBlock.FontWeight="Bold" HorizontalAlignment="Left">

                        <Grid.ColumnDefinitions>

                            <ColumnDefinition Width="80"/>

                            <ColumnDefinition Width="*"/>

                        </Grid.ColumnDefinitions>

                    </Grid>

                    <Grid x:Name="GMB_Code"  

                            TextBlock.FontSize="15" TextBlock.FontWeight="Bold" HorizontalAlignment="Left">

                        <Grid.ColumnDefinitions>

                            <ColumnDefinition Width="80"/>

                            <ColumnDefinition Width="*"/>

                        </Grid.ColumnDefinitions>

                    </Grid>

                    <TextBlock/>

                    <StackPanel x:Name="GMB_Info" Orientation="Vertical"/>

                    <TextBlock/>

                    <TextBlock x:Name="GMB_SolnTxT" TextAlignment="Center" 

                           FontSize="15" FontWeight="Bold" HorizontalAlignment="Left"

                           VerticalAlignment="Center" />

                    <StackPanel x:Name="GMB_Soln" Orientation="Vertical"/>

                </StackPanel>

            </ScrollViewer>

        </AdornerDecorator>

        <StackPanel x:Name="GMB_Bottom" Orientation="Horizontal" HorizontalAlignment="Right" Grid.Row="2" Margin="0,5,10,10" />

    </Grid>

</Border>
</Window>
```why does this phenomenon occur?

are there any known workarounds to force proper rendering on initial ShowDialog()?

Viorel 123.6K Reputation points

2025-08-01T19:45:41.27+00:00

How is the background color set?

Chris 0

The whole window background color was set transparent.

GMB_Border background be set #FF3969B2(a medium blue with a slight grayish tint)

GMB_Title background be set

    <LinearGradientBrush x:Key="MessageBoxHeaderBrush" StartPoint="0.5,0" EndPoint="0.5,1">
        <GradientStop Offset="0" Color="Transparent"/>
        <GradientStop Offset="0.5" Color="Transparent"/>
        <GradientStop Offset="1" Color="Transparent"/>
    </LinearGradientBrush>

Starry Night 30 Reputation points

2025-08-04T08:15:45.85+00:00

You can try to use the latest framework .Net 8.0 or .Net 9.0 and try again.
Starry Night 30 Reputation points

2025-08-05T07:31:12.95+00:00

I find there is a similar issue about this, you can check it here: Button renders wrong after mouse leave.
Starry Night 30 Reputation points

2025-08-07T08:10:22.3366667+00:00

Based on your code, I created a new demo, but the UI of result is not like the one in your screenshot. Could you please post the full code of this UI so that we can try to reproduce this problem?

Chris 0

you can add a button to main window, main window backend code is as bellow.

    private  void buttonItem_Click(object sender, RoutedEventArgs e)

    {

        var buttonItem = sender as Button;

        string szTitle = buttonItem.Content.ToString();

        int nIdentifier = (int)buttonItem.Tag;

        StackPanel bottomPanel = buttonItem.Parent as StackPanel;

        messageBoxList[nIdentifier]?.Close();

        if (messageBoxList.ContainsKey(0) == true)

        {

            messageBoxList.Remove(0);

        }

    }public partial class MainWindow : Window

{

    internal static Dictionary<int, TransparentDialog> messageBoxList = new Dictionary<int, TransparentDialog>();

    public MainWindow()

    {

        InitializeComponent();

        RenderOptions.ProcessRenderMode = RenderMode.SoftwareOnly;

        Debug.WriteLine($"Render titer = {(RenderCapability.Tier >> 16)}");

    }

    private void Button_Click(object sender, RoutedEventArgs e)

    {

        var messageBox = new TransparentDialog();

        messageBox.solnText.Text = "Solutions\n";

        messageBox.txtTitle.Text = "PR Feature Operation";

        SetMessageBox(messageBox);

        messageBox.ShowDialog();

        Debug.WriteLine($"Render titer = {(RenderCapability.Tier >> 16)}");

    }

    private  void buttonItem_Click(object sender, RoutedEventArgs e)

    {

        var buttonItem = sender as Button;

        string szTitle = buttonItem.Content.ToString();

        int nIdentifier = (int)buttonItem.Tag;

        StackPanel bottomPanel = buttonItem.Parent as StackPanel;

        messageBoxList[nIdentifier]?.Close();

        if (messageBoxList.ContainsKey(0) == true)

        {

            messageBoxList.Remove(0);

        }

    }

   private void SetMessageBox(TransparentDialog messageBox)

   {

        string sPath = "MessageBoxBlue_FlatStyle2.xaml";

        Uri uri = new Uri(sPath, UriKind.Relative);

        ResourceDictionary rd = Application.LoadComponent(uri) as ResourceDictionary;

        messageBox.Resources = rd;

        messageBox.solnText.Foreground = (SolidColorBrush)rd["SolnTextForeground"];

        messageBox.imgTitle.Source = (ImageSource)rd["MessageBoxIcon"];

        messageBox.border.Style = (Style)rd["MessageBoxBorderStyle"];

        messageBox.gridTitle.Background = (LinearGradientBrush)rd["MessageBoxHeaderBrush"];

        messageBox.txtTitle.Style = (Style)rd["MessageBoxTitle"];

        messageBox.closeBtn.Content = (System.Windows.Shapes.Path)rd["CloseButtonPath"];

        messageBox.closeBtn.Style = (Style)rd["CloseButton"];

        string[] sInfoArray = { "Would You Like To Perform 30 times PR?" };

        if (sInfoArray != null)

        {

            foreach (string sInfoItem in sInfoArray)

            {

                if (sInfoItem != null)

                {

                    TextBlock text = new TextBlock();

                    text.Text = sInfoItem;

                    text.Style = (Style)rd["MessageBoxContent"];

                    messageBox.infoPanel.Children.Add(text as UIElement);

                }

            }

        }

        messageBox.solnPanel.Visibility = Visibility.Collapsed;

        messageBox.solnText.Visibility = Visibility.Collapsed;

        string[] btnContentArray = { "Yes", "Cancel" };

        if (btnContentArray != null)

        {

            double dMaxLength = 0;

            foreach (string btnContentItem in btnContentArray)

            {

                if (btnContentItem.Length > dMaxLength)

                    dMaxLength = btnContentItem.Length;

            }

            foreach (string btnContentItem in btnContentArray)

            {

                if (btnContentItem != null)

                {

                    Button buttonItem = new Button();

                    buttonItem.MinWidth = 60;

                    buttonItem.Width = dMaxLength * 8;

                    buttonItem.Content = btnContentItem;

                    buttonItem.Style = (Style)rd["ClickButton"];

                    messageBox.bottomPanel.Children.Add(buttonItem as UIElement);

                    buttonItem.Tag = 0;

                    buttonItem.Click += new RoutedEventHandler(buttonItem_Click);

                }

            }

            if (messageBoxList.ContainsKey(0) == false)

            {

                messageBoxList.Add(0, messageBox);

            }

        }

    }

}
```Style

```xml
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"   
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

                xmlns:Local="clr-namespace:MessageboxDispalyTesting">

<ResourceDictionary.MergedDictionaries>

    <ResourceDictionary Source="/PresentationFramework.Aero, Version=3.0.0.0, Culture=neutral,PublicKeyToken=31bf3856ad364e35, ProcessorArchitecture=MSIL;component/themes/aero.normalcolor.xaml" />

</ResourceDictionary.MergedDictionaries>

<!--MessageBox Icon image-->

<ImageSource x:Key="MessageBoxIcon" >HelpInfo.png</ImageSource>

<!-- Brushes. -->

<SolidColorBrush x:Key="CloseButtonBackgroundBrush" Color="White"/>

<SolidColorBrush x:Key="CloseButtonBorderBrush" Color="Transparent"/>

<SolidColorBrush x:Key="CloseButtonFocusBorderBrush" Color="AliceBlue"/>

<SolidColorBrush x:Key="CloseButtonMouseOverBrush" Color="AliceBlue"/>

<SolidColorBrush x:Key="CloseButtonPressedBackgroundBrush" Color="GhostWhite"/>

<SolidColorBrush x:Key="CloseButtonPressedHighlightBrush" Color="GhostWhite"/>

<SolidColorBrush x:Key="CloseButtonShineBrush" Color="Transparent"/>

<SolidColorBrush x:Key="MessageBoxBackgroundBrush" Color="#FF3969B2"/>

<SolidColorBrush x:Key="MessageBoxBorderBrush" Color="#FF3969B2"/>

<LinearGradientBrush x:Key="MessageBoxHeaderBrush" StartPoint="0.5,0" EndPoint="0.5,1">

    <GradientStop Offset="0" Color="Transparent"/>

    <GradientStop Offset="0.5" Color="Transparent"/>

    <GradientStop Offset="1" Color="Transparent"/>

</LinearGradientBrush>

<SolidColorBrush x:Key="MessageBoxTitleBrush" Color="White" />

<SolidColorBrush x:Key="DropDownBtnBackground" Color="White"/>

<SolidColorBrush x:Key="DropDownBtnBorder" Color="White"/>

<SolidColorBrush x:Key="DropDownBtnHightlightBrush" Color="GhostWhite"/>

<SolidColorBrush x:Key="CloseButtonForeground" Color="White" />

<SolidColorBrush x:Key="CloseButtonHighlightForeground" Color="White" />

<SolidColorBrush x:Key="ButtonForeground" Color="Black" />

<SolidColorBrush x:Key="ButtonHighlightForeground" Color="Black" />

<SolidColorBrush x:Key="ContentForeground" Color="White" />

<SolidColorBrush x:Key="SolnTextForeground" Color="White" />

<!-- Styles. -->

<Style x:Key="DialogWindow" TargetType="{x:Type Window}">

    <Setter Property="Margin" Value="5" />

    <Setter Property="ResizeMode" Value="NoResize" />

    <Setter Property="WindowStyle" Value="None" />

    <Setter Property="AllowsTransparency" Value="True"/>

    <Setter Property="MaxWidth" Value="1000" />

    <Setter Property="MaxHeight" Value="700" />

    <Setter Property="ShowInTaskbar" Value="False"/>

    <Setter Property="Template">

        <Setter.Value>

            <ControlTemplate TargetType="{x:Type Window}">

                <Border x:Name="border"

                        BorderThickness="5"

                        CornerRadius="4,4,4,4"

                        Background="{DynamicResource MessageBoxBackgroundBrush}" 

                        BorderBrush="{DynamicResource MessageBoxBorderBrush}">

                    <Grid>

                        <Grid.RowDefinitions>

                            <RowDefinition Height="30" />

                            <RowDefinition />

                        </Grid.RowDefinitions>

                        <Grid x:Name="PART_Title" Background="{DynamicResource MessageBoxHeaderBrush}" >

                            <Grid.ColumnDefinitions>

                                <ColumnDefinition />

                                <ColumnDefinition Width="30" />

                            </Grid.ColumnDefinitions>


          

                            <Button x:Name="PART_Close"

                                        Content="{DynamicResource CloseButtonPath}"

                                        Grid.Column="1"

                                        Style="{DynamicResource CloseButton}"

                                        Padding="4" />

                        </Grid>

                        <AdornerDecorator Grid.Row="1">

                            <ContentPresenter Content="{TemplateBinding Content}" Margin="{TemplateBinding Margin}" />

                        </AdornerDecorator>

                    </Grid>

                </Border>

            </ControlTemplate>

        </Setter.Value>

    </Setter>

</Style>

<Style x:Key="MessageBoxBorderStyle" TargetType="{x:Type Border}">

    <Setter Property="CornerRadius" Value="0"/>

    <Setter Property="BorderThickness" Value="1"/>

    <Setter Property="BorderBrush" Value="{StaticResource MessageBoxBorderBrush}"/>

    <Setter Property="Background" Value="{StaticResource MessageBoxBackgroundBrush}"/>

</Style>

<Style x:Key="MessageBoxTitle" TargetType="{x:Type TextBlock}">

    <Setter Property="FontSize" Value="20"/>

    <Setter Property="FontWeight" Value="Bold" />

    <Setter Property="Foreground" Value="{DynamicResource MessageBoxTitleBrush}" />

</Style>

<Style x:Key="MessageBoxContent" TargetType="{x:Type TextBlock}">

    <Setter Property="FontSize" Value="15"/>

    <Setter Property="FontFamily" Value="Arail" />

    <Setter Property="HorizontalAlignment" Value="Left" />

    <Setter Property="VerticalAlignment" Value="Center" />

    <Setter Property="Foreground" Value="White" />

</Style>

<Path x:Key="CloseButtonPath"

          Data="M1,1 L7.4999998,7.334 M7.4999998,1 L0.99999997,7.334"

          Stretch="Fill"

          Stroke="{DynamicResource CloseButtonForeground}"

          StrokeEndLineCap="Round"

          StrokeStartLineCap="Round"

          StrokeThickness="2" />

<Path x:Key="CloseButtonPath_TouchScreen"

          Data="M1,1 L7.4999998,7.334 M7.4999998,1 L0.99999997,7.334"

          Stretch="Fill"

          Stroke="{DynamicResource CloseButtonForeground}"

          StrokeEndLineCap="Round"

          StrokeStartLineCap="Round"

          StrokeThickness="2"/>
```</ResourceDictionary>

![HelpInfo](/api/attachments/0fe2c502-0122-4b14-8153-538991e1dfc9?platform=QnA)

Chris 0 Reputation points

2025-08-08T05:56:25.36+00:00

I use this command dxdiag /t dxinfo.txt to check hardware info, I find this, I'm not sure if this caused this render error. This can ‘t be reproduced, it only occurs occasionally.

Your answer

Viorel 123.6K Reputation points

2025-08-01T19:45:41.27+00:00

How is the background color set?
Chris 0 Reputation points

2025-08-04T02:09:18.8066667+00:00

The whole window background color was set transparent.

GMB_Border background be set #FF3969B2(a medium blue with a slight grayish tint)

GMB_Title background be set

<LinearGradientBrush x:Key="MessageBoxHeaderBrush" StartPoint="0.5,0" EndPoint="0.5,1"> <GradientStop Offset="0" Color="Transparent"/> <GradientStop Offset="0.5" Color="Transparent"/> <GradientStop Offset="1" Color="Transparent"/> </LinearGradientBrush>
Starry Night 30 Reputation points

2025-08-04T08:15:45.85+00:00

You can try to use the latest framework .Net 8.0 or .Net 9.0 and try again.
Starry Night 30 Reputation points

2025-08-05T07:31:12.95+00:00

I find there is a similar issue about this, you can check it here: Button renders wrong after mouse leave.
Starry Night 30 Reputation points

2025-08-07T08:10:22.3366667+00:00

Based on your code, I created a new demo, but the UI of result is not like the one in your screenshot. Could you please post the full code of this UI so that we can try to reproduce this problem?
Chris 0 Reputation points

2025-08-08T05:56:25.36+00:00

I use this command dxdiag /t dxinfo.txt to check hardware info, I find this, I'm not sure if this caused this render error. This can ‘t be reproduced, it only occurs occasionally.

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WPF Modal window not rendering title area on initial ShowDialog() until mouse move

Your answer