ASP.NET C＃ListBox服务器控件不会禁用

I have 4 server side ListBox controls. All of them have their Enabled property set to false, yet when rendered they are definitely enabled. They are all multiple select. These have no data binding or any code behind touching them. Below is the markup for all of them (save the ID). I am running v4 of the .NET Framework with IIS6.I have 4 server side ListBox controls. All of t