Gorm (Graphic Object Relationship Modeller) is a GNUstep application for building user interfaces and application objects relationships. Its major features include drag-and-drop creation of GUI elements from palettes, run-time loading of additional palettes, direct on-screen manipulation of GUI elements, manipulation and examination of objects via inspectors, and creation of connections between objects using mouse. It is a clone of the former NeXTstep (currently OS X) "Interface Builder" application.
Setedit is a text editor specially designed for programmers. It has a nice interface with mouse support, menus and windows (text mode). The editor is a very good choice for people with DOS background, especially people accustomed to Worstar and Borland editors. The editor has overlapped windows so you can see more than one file at the same time, configurable syntax highlighting, macros, rectangular selection, block indentation, as well as customizable keyboard shortcuts and menus.
Squeak is an OpenSource and super-portable implementation of a multi-media capable Smalltalk-80 based object-oriented programming environment. It is written entirely in Smalltalk and has a high-performance VM, created by compiling the Smalltalk VM code into efficient and portable C code. It now uses the Self language's Morphic User Interface but still provides the original MVC GUI as well.
CLIP is a Clipper/XBase compatible compiler with initial support other xBase dialects. It features support for international languages and character sets. It also features OOP, a multiplatform GUI based on GTK/GTKextra, all SIX/Comix features (including hypertext indexing), SQL and ODBC drivers, a C-API for third-party developers, a few wrappers for popular libraries (such as BZIP, GZIP, GD, Crypto, and Fcgi), a multitasking client and application server based on TCP/IP sockets, object data base utilities, and a functions library.
JGraph is a free, mature, and robust Java diagramming library. It contains all the graph visualization, layout, and interaction functionality you might expect in a graph library, including multiple views, layering, zoom, drag and drop, undo, automatic expanding and collapsing, routing, and layouts. You can create workflow editors, BPMN, CAD tools, network diagrams, database visualization tools, and more. It is fully documented, including examples, and has an active support community.
The Oculus Layout System supplies a Java layout API, and an easy-to-use visual builder, which works with both Swing and AWT. Main features include a proprietary stretching model, which enables the system to automatically infer how to properly stretch almost any user interface, and a cursor-based layout paradigm which dramatically improves the readability and maintainability of the layout code.
Steph is a portable C library for text mode windows, menus, dialogs, etc. The interface with the underlying system is provided by a separate library, so to port to a new system, only the interface library needs to be rewritten. Interface libraries are provided for Unix/Curses and IBM PC compatibles running DOS.
Eric is a full featured Python and Ruby editor and IDE, written in Python. It is based on the cross platform Qt GUI toolkit, integrating the highly flexible Scintilla editor control. It is designed to be usable as an everyday quick and dirty editor as well as being usable as a professional project management tool, integrating many advanced features that Python offers the professional coder. Eric includes a plug-in system, which allows easy extension of the IDE functionality with plug-ins downloadable from the net. Current stable versions are Eric4 based on Qt4 and Python 2 and Eric5 based on Python 3 and Qt4.