support won't be enabled by default in the forthcoming release of X Server 1.6
even though it landed in the mainline code-base
last year. This technology to allow for multiple input devices to be used on Linux simultaneously will not be enabled by default until X Input 2.0
arrives with X Server 1.7
later this year. However, that isn't stopping GNOME developers from already working on GTK+ support for X Input 2.0 and Multi-Pointer X.
Carlos Garnacho has been working on adding X Input 2.0 support to the GDK by adding in a GtkDeviceGroup multidevice-event signal. The GtkDeviceGroup is a container for grouping GdkDevices, hence its name. There has also been a few API changes to GTK+ and other work to incorporate X Input 2.0 / MPX. There is also a fair amount of work left, which is detailed on the GTK+ MPX Wiki
More information on the work done by Carlos can be found on his blog
. There is a GTK+ MPX Git repository
for those interested in trying out a version of GTK+ with multiple pointers before it enters the mainline GTK+ code-base.