It can't be related to GTK. It must be related to drivers, Compiz or Xorg - sth low level, it's system wide, not limited to apps, try using your tablet as mouse - the same problem occurs.
It can't be related to GTK. It must be related to drivers, Compiz or Xorg - sth low level, it's system wide, not limited to apps, try using your tablet as mouse - the same problem occurs.