feat: init avalonia demo.

src/Shared/HandyControl_Shared/Themes/Styles/Base/TabControlBaseStyle.xaml

@@ -84,8 +84,8 @@
                             <RowDefinition x:Name="RowDefinition0" Height="Auto" />
                             <RowDefinition x:Name="RowDefinition1" Height="*" />
                         </Grid.RowDefinitions>
-                        <TabPanel x:Name="headerPanel" Background="Transparent" Grid.Column="0" IsItemsHost="true" Margin="0" Grid.Row="0"/>
-                        <Border x:Name="contentPanel" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{DynamicResource BorderBrush}" Background="{TemplateBinding Background}" Grid.Column="0" Grid.Row="1">
+                        <TabPanel x:Name="headerPanel" Background="Transparent" IsItemsHost="true" Margin="0" Grid.Row="0"/>
+                        <Border x:Name="contentPanel" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{DynamicResource BorderBrush}" Background="{TemplateBinding Background}" Grid.Row="1">
                             <ContentPresenter x:Name="PART_SelectedContentHost" ContentSource="SelectedContent" Margin="0" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                         </Border>
                     </Grid>

src/Shared/HandyControl_Shared/Tools/Helper/ConfigHelper.cs

@@ -20,7 +20,9 @@ public class ConfigHelper : INotifyPropertyChanged
 
     }
 
-    public static ConfigHelper Instance = new Lazy<ConfigHelper>(() => new ConfigHelper()).Value;
+    private static readonly Lazy<ConfigHelper> InstanceInternal = new(() => new ConfigHelper(), isThreadSafe: true);
+
+    public static ConfigHelper Instance => InstanceInternal.Value;
 
     private XmlLanguage _lang = XmlLanguage.GetLanguage("zh-cn");