Themes are constituted by run-time loadable bundles which change or
customize the appearance of the graphical interface.
Themes can be set for all application or also each application can loads its own theme, allowing for a high level of adaptability.
To change the system-wide theme, look at the Theme Module of System Preferences
Many interface element styles can be customized in GNUstep. The
standard interface has a feel which follows that of NeXT and which
feels different than that of most graphical environments which
essentially follow the CUA style (Windows-Motif/CDE-OS/2). GNUstep is
capable of changing the behaviour of several controls and elements . We
encourage you to try out the default style: it needs some time to adapt
to when coming from a different system, but it is very functional.
However, when there is need to integrate a GNUstep application in a
foreign environment, it can be desired to make it blend best. Slowly
other environments acquired some of the NeXT prerogatives, blurring the
differences. These interface parameters can be set simply by writing
defaults, but a theme bundle can conveniently set them together.
Menu Style: NeXT-style (floating-detachable and vertical), Macintosh-style (persistent, top of the screen), Windows-style (in-window)
Scrolling arrows: NeXT-style (paired, at the bottom), Windows-style (one at each end)
Scroll bar: at the right (NeXT style) or at right.
Windows decorations: drawn by the host system (typically the X11 window manager) or by GNUstep itself (allowing to theme them)
Theming support in GNUstep-gui is pretty advanced, however the
native themes and Thematic are still under development.
The Native themes may support some controls but do not behave well generaly with every application. It is best to test how well your application fares, changes are it may work very well already.
There has been no official Thematic release yet.
There have not been any officially releases of the themes.