# System.Drawing.Design

``` diff
 namespace System.Drawing.Design {
     public class ToolboxItem : ISerializable {
-        public AssemblyName[] DependentAssemblies { get; set; }
+        public AssemblyName[]? DependentAssemblies { get; set; }
-        public IComponent[] CreateComponents();
+        public IComponent[]? CreateComponents();
-        public IComponent[] CreateComponents(IDesignerHost host);
+        public IComponent[]? CreateComponents(IDesignerHost host);
-        public IComponent[] CreateComponents(IDesignerHost host, IDictionary defaultValues);
+        public IComponent[]? CreateComponents(IDesignerHost host, IDictionary defaultValues);
-        protected virtual IComponent[] CreateComponentsCore(IDesignerHost host);
+        protected virtual IComponent[]? CreateComponentsCore(IDesignerHost host);
-        protected virtual IComponent[] CreateComponentsCore(IDesignerHost host, IDictionary defaultValues);
+        protected virtual IComponent[]? CreateComponentsCore(IDesignerHost host, IDictionary defaultValues);
-        void System.Runtime.Serialization.ISerializable.GetObjectData(SerializationInfo info, StreamingContext context);
+        void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context);
-        protected void ValidatePropertyType(string propertyName, object value, Type expectedType, bool allowNull);
+        protected void ValidatePropertyType(string propertyName, object? value, Type expectedType, bool allowNull);
     }
 }
```

