GadToolsBox v3 is a powerful GUI generator for AmigaOS. It uses gadtools.library and some other external gadgets. With GTB v3 You can highly expand your GUI with a lot of features like toolbars, tree listviews, page gadgets, clipboards. GTB v3 is something like resource editor, You can create here almost everything using all of OS features. You can draw pictures, mouse pointers, edit locale strings, create menus, windows, toolbars, version strings and much more, everything with one program.
Generated source code is similiar to very well known source code generated by old GadToolsBox by Jaba Development. So, turning to new GTB is very easy, but programs need to be reworked (there are a new functions and there is other naming convention). Of course GTB v3 can load old resources from GadToolsBox v2 (all #?.gui files), but you cannot load GTB v1 resources.
GadToolsBox source is provided AS IS. You can use it in any form.