Created attachment 204496 [details]
An image with stray lines

Prerequisites:
Gimp 2.6.11 installed on Ubuntu Ocelot
Trust slimline Tablet successfully installed
Tablet pressure working perfectly in Pencil (drawing program)

Steps to reproduce:
First Setup:
1 Attach tablet
2 Start Gimp
3 Setup pressure in edit->preferences->input devices->configure extended input devices
4 Select the trust stylus
4.a set mode to "Screen"
5 leave the defaults
6 Click save and close


Then Draw:
1 Create new drawing
2 select paintbrush
3 start drawing
OBSERVE - the pressure is working as expected
4 at (seemingly) random, a line is drawn from the current paintbrush position to the edge of the image window. 
The behaviour sometimes occurs first time after a minute or two. Mostly it occurs within the first 30 seconds. It seems more likely that it will happen when I change tools.
The lines seem to point to (current x, 0) or (0, current y) or (0,0). The behaviour is so annoying, that I can not use the pressure feature of the tablet with Gimp.