C# - App.Config Custom Configuration Section

I've created a custom config section for my application. For some reason Visual Studio 2010 isn't picking up and of my custom properties. I'm getting warnings similar to this for all the "add" keys: Could not find schema information for the element 'urlFilterSection'

CONFIG FILE:
<configSections>
<section name="urlFilterSection" type="BotFinderApp.Models.UrlFilterSection, BotFinder" />
</configSections>
<urlFilterSection>
<urlFilterCollection>
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
<add url="urlhere.com.au" numberOfIpsToExtract="10" />
</urlFilterCollection>
</urlFilterSection>
UrlFilterSection:
namespace BotFinderApp.Models
{
public class UrlFilterSection : ConfigurationSection
{
public UrlFilterSection()
{
}
[ConfigurationProperty("urlFilterCollection", IsDefaultCollection = false)]
[ConfigurationCollection(typeof(UrlFilterCollection), AddItemName = "add", ClearItemsName = "clear", RemoveItemName = "remove")]
public UrlFilterCollection Urls
{
get
{
var urlsCollection = (UrlFilterCollection)base["urlFilterCollection"];
return urlsCollection;
}
}
}
}
UrlFilterCollection
namespace BotFinderApp.Models
{
public class UrlFilterCollection : ConfigurationElementCollection
{
public UrlFilterCollection()
{
}
protected override ConfigurationElement CreateNewElement()
{
return new UrlFilter();
}
protected override object GetElementKey(ConfigurationElement element)
{
return ((UrlFilter)element).Url;
}
}
}
UrlFilter
namespace BotFinderApp.Models
{
public class UrlFilter : ConfigurationElement
{
public UrlFilter()
{
}
[ConfigurationProperty("url", DefaultValue = "", IsRequired = true)]
public string Url
{
get { return (string)this["url"]; }
set { this["url"] = value; }
}
[ConfigurationProperty("numberOfIpsToExtract", DefaultValue = "0", IsRequired = true)]
public int NumberOfIpsToExtract
{
get { return (int)this["numberOfIpsToExtract"]; }
set { this["numberOfIpsToExtract"] = value; }
}
}
}