Anjuta (in the 
anjuta package) and GNOME Builder (in the 
gnome-builder package) are Integrated Development Environments (
IDE) optimized for creating GTK+ applications for GNOME. Glade (in the 
glade package) is an application designed to create GTK+ graphical interfaces for GNOME and save them in an XML file. These XML files can then be loaded by the GTK+ shared library through its 
GtkBuilder component to recreate the saved interfaces; such a feature can be interesting, for instance for plugins that require dialogs.