>>>Hmmm. Works for me. Given this file in a project named Members:

namespace Members.Library
>>>{
>>>    public class Class1
>>>    {
>>>    }
>>>}

>>>then the following WPF XAML shows the Library.Members namespace in Intellisense and ends up like this:

<Window x:Class="WpfApplication1.Window1"
>>>    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
>>>    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>>>    xmlns:Members="clr-namespace:Members.Library;assembly=Members" >
>>></Window>

>>
>>I just tried something similar and it worked in the test (well the intellisense didn't show me what I expected) and the error does not show up. This is really weird. Maybe I need to start everything over from scratch? Aargh, this is really frustrating.
>
>Did Intellisense show *anything* related to the Members.Library project?

nope