Gridbox - Create beautiful landing pages in seconds.
wxWidgets - wxWidgets: Cross-Platform GUI Library
SitePM - Creating and designing websites easier than ever before using the powerful features of SitePM. SitePM is a web content management system (WCMS) offered as a Software as a Service model.
Electron - Build cross platform desktop apps with web technologies
Gomymobi - Gomymobi is a website builder
GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.