I am following exercises in a SP2010 Visual Studio 2010 book and I am using SP 2010 Foundations only. I am at the point (External Content Types) with my Model where I want to add the name value pair in the property editor for my LobSystemInstance. So, under Custom properties (Collection) I click the ellipses to view the property editor. Regardless of what I do, I get a red exclamation icon and the Add and OK buttons are grayed out as soon as I click on any field within. Hovering over the icon tells me to "Please enter a value". As a further note, I notice this same behavior any time I click on the ellipses for other Custom Properties.