GPE themes consist of two parts which need to play together. These are a GTK+ theme and a Matchbox theme. The matchbox theme covers window decoration, default background, menu design, desktop icons. The GTK theme covers application look like stock icons, button design, sliders and other widgets. The themes usually consist of description files which are found in the /usr/share/themes directory. Some of the GTK themes make use if a GTK theming engine which is installed as a shared library.