QSuperList is a virtually codeless listbox for Qt. It provides a listbox with a plus and minus button that handles additions and subtractions to the listbox. The number of items, length of items, allowance of blank values are also set from simple member functions once. Editing an item is just a doubleclick in the listbox.
picoTK is a C GUI toolkit that requires only a minimum of memory resources. It is intended for embedded system use, especially for (but not limited to) the RTEMS realtime kernel. It is in no way comparable featurewise to a "real" full blown windows toolkit like Qt or nanoX; it rather provides simple drawing primitives like lines, filled rectangles, characters, and pixmaps. (But that is what many embedded applications might ask for.) It directly works on tailored "framebuffer" hardware. A Linux framebuffer emulator is supplied as part of the kit, making evaluation (and emulation!) possible without having a realtime OS and custom hardware.
GtkCanvas is a straight port of the GNOME Canvas from the stable gnome-libs 1.2.4 back to gtk+. This widget behaves identically to the GnomeCanvas widget, with the same APIs, except the names are changed from gnome_canvas to gtk_canvas. Since the next version of gtk+ will drop GdkImLib and intgrate with gdk-pixbuf, it is expected that future versions of this widget will depend upon gtk+ only. It is intended that GtkCanvas will follow GnomeCanvas closely, merging new code whenever a stable release of the latter is made. Thus this is not really a fork but rather a "re-packaging" of the same code.
DiaCanvas is a generalized version of the drawing canvas used by DIA. It extends some features used by DIA and adds new ones, while preserving as many of the original features as possible. This project is no longer actively maintained. It is suggested that you try DiaCanvas2 instead.