优化更新代码，添加界面功能并整合

WPFluent/Controls/Menu/MenuLoader.xaml.cs

@@ -0,0 +1,34 @@
+
+
+
+using System.Reflection;
+
+namespace WPFluent.Controls;
+
+/// <summary>
+/// Changes readonly field value of <see cref="SystemParameters.MenuDropAlignment"/> to false.
+/// </summary>
+public partial class MenuLoader : ResourceDictionary
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="MenuLoader"/> class.
+    /// </summary>
+    /// <remarks>
+    /// Sets menu alignment on initialization.
+    /// </remarks>
+    public MenuLoader() { MenuLoader.Initialize(); }
+
+    private static void Initialize()
+    {
+        if(!SystemParameters.MenuDropAlignment)
+        {
+            return;
+        }
+
+        FieldInfo? fieldInfo = typeof(SystemParameters).GetField(
+            "_menuDropAlignment",
+            BindingFlags.NonPublic | BindingFlags.Static);
+
+        fieldInfo?.SetValue(null, false);
+    }
+}