In my UI XAML I\'m essentially inheriting from a class \"BaseView\" that contains functionality common to several forms, however this is preventing the designer from display
I found a very useful solution to this on : http://www.progware.org/Blog/post/WPF-Designer-Error-Could-not-create-an-instance-of-type.aspx.
This link explains how the WPF designer window runs the Constructor to display the UI in XAML and the remedy: adding the following snippet to any part of constructor code which might be giving error:
if(!System.ComponentModel.DesignerProperties.GetIsInDesignMode(this))
{
//code producing exception
}
the function name is self explanatory. :) This link also provides solutions on debugging issues with XAML.