I'm also having the exact same issue, which makes it almost impossible to draw anything. System is Ubuntu 11.04 with all the latest updates, Gimp 2.6.11 and a Wacom Bamboo Pen CTL-460 using driver xserver-xorg-input-wacom version 0.10.11-0ubuntu9. The strange thing is that sometimes it does work, but I'm still not sure what triggers the correct behaviour. Very very annoying!
I'm also having the exact same issue, which makes it almost impossible to draw anything. System is Ubuntu 11.04 with all the latest updates, Gimp 2.6.11 and a Wacom Bamboo Pen CTL-460 using driver xserver- xorg-input- wacom version 0.10.11-0ubuntu9. The strange thing is that sometimes it does work, but I'm still not sure what triggers the correct behaviour. Very very annoying!