Created attachment 187050 [details]
screen photo with bug

When I paint with a brush, I get the following bug from time to time, but often enough to become uncomfortable to work.

FYI: 
* OS - Ubuntu Linux 11.4
* Tablet - Wacom Intuos4 - This tablet monitors the movement of the stylus on the tablet surface (without touching).

I touch the stylus to the tablet and draw the line. Then I lift the stylus from the tablet, and move the stylus. In this case, the pointer cursor moves, but the brush cursor does not (still placed at the last point). Then, I move the stylus cursor (pointer) to a new point, and drop the stylus on the tablet (touching), and move pointer to next point (drawing another line). On the screen I see that the line is not drawn: brush cursor placed at the starting point of a new line and the pointer cursor moves around the screen.

See my screen photo (cause screenshot does not save cursors). My marks in red.