Gwen.Net Ex is a port of Gwen.Net which is a .Net port of GWEN. GWEN is a lightweight GUI library aimed at games. It contains rich widget collection and most functionality you'd expect from a GUI framework. Gwen.Net is a .NET C# conversion of GWEN. Gwen.Net Ex has a new two-pass layout engine, support for UI creation using XML and new controls. It includes also a simple XML designer to help creating an UI with XML.
Original GWEN can be found from https://github.com/garrynewman/GWEN and Gwen.Net from https://code.google.com/archive/p/gwen-dotnet