TMyCompEditor = class(TComponentEditor)
 private
   FPropInfo: PPropInfo;
   FPropEdit: IProperty;
   procedure GetPropProc(const PropEdit: IProperty);
 public
   constructor Create(AComponent: TComponent; ADesigner: IDesigner); override;
   procedure ExecuteVerb(Index: Integer); override;
   function GetVerb(Index: Integer): string; override;
   function GetVerbCount: Integer; override;
 end;

procedure Register;
begin
 RegisterComponents('YzExamples', [TMyComp]);
 RegisterComponentEditor(TMyComp, TMyCompEditor)
end;

{ TMyCompEditor }

constructor TMyCompEditor.Create(AComponent: TComponent; ADesigner: IDesigner);
begin
 inherited;
 FPropInfo := GetPropInfo(GetComponent.ClassInfo, 'MyItems', [tkClass])
end;

procedure TMyCompEditor.ExecuteVerb(Index: Integer);
var
 Selections: TDesignerSelections;
begin
 if Index = GetVerbCount - 1 then
 begin
   if (FPropEdit = nil) and (FPropInfo <> nil) then
   begin
     Selections := TDesignerSelections.Create;
     try
       Designer.GetSelections(Selections);
       GetComponentProperties(Selections, [tkClass], Designer, GetPropProc)
     finally
       Selections.Free
     end
   end;
   if FPropEdit <> nil then
     FPropEdit.Edit
 end
 else
   inherited
end;

procedure TMyCompEditor.GetPropProc(const PropEdit: IProperty);
begin
 if PropEdit.GetPropInfo = FPropInfo then
   FPropEdit := PropEdit
end;

function TMyCompEditor.GetVerb(Index: Integer): string;
begin
 if Index = GetVerbCount - 1 then
   Result := 'MyItems Editor...'
 else
   Result := inherited GetVerb(Index)
end;

function TMyCompEditor.GetVerbCount: Integer;
begin
 Result := inherited GetVerbCount + 1
end;