C # WPF - Black line in window

Question

In my window trere a little black line. Why?

<Window x:Class="WpfPortOfTestingCamera.InputSelection" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="InputSelection" WindowStartupLocation="CenterOwner" ResizeMode="NoResize" ShowInTaskbar="False" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" SizeToContent="WidthAndHeight" d:DesignWidth="280" d:DesignHeight="206"> <StackPanel HorizontalAlignment="Center" Name="stackPanel1" VerticalAlignment="Top" Margin="10" MaxWidth="500"> <GroupBox Header="Select Camera" HorizontalAlignment="Center" VerticalAlignment="Center"> <ComboBox Height="23" Name="comboBox1" HorizontalAlignment="Center" VerticalAlignment="Center" MinWidth="120" /> </GroupBox> <Button Content="OK" Name="ButtonOK" IsDefault="True" Click="ButtonOK_Click" /> </StackPanel> </Window> 

Answer 1

This seems to be a rendering artifact that occurs when the window is resized to the width of your combo box when setting the content line.

If you add the SnapsToDevicePixels = "True" attribute to the Window tag, the black line disappears.