In addition to a thorough cleanup of the stock code, the developers of Gtk + (GIMP Toolkit) have also introduced innovations. This druchgehende the use of Cairo is part of the Drawing. The obsolete X11 drawing API has disappeared.

In addition, the toolkit is now Xinput 2 (XI2) and can therefore deal with several pointing devices and keyboards. For this integration, Matthias Clasen thanks in his blog entry for the release
From the same developer is also a new theming API, the Gtk + applications by using CSS syntax including animated transitions embellished.

Other enhancements include more flexible geometry management and support for different backends like X11, Wayland or quartz in Gimp Drawing Kit GDK. In addition, the developer, the messaging system D-Bus in the file system utilities have integrated by GIO.

The updated documentation for Gtk + 3.0 is available in the Gnome Documentation Library. The LGPL licensed Gtk + source code is under HTTP or FTP to have.