Comment 2 for bug 1005321

I've just found bug Bug #774938 and think that the erratic mouse cursor movement that I described right after "Besides, there are several other problems related to the touchscreen itself:" is related to that bug.
I use a dual monitor configuration and I'm using coordinate transformation matrix to restrict the touchscreen to one of my monitors. I use two 1920x1080 monitors positioned one above the other. The bottom monitor has a touchscreen, but the upper monitor does not. Without modifying the coordinate transformation matrix, X thinks that the touchscreen covers the entire desktop. I use the following command to restrict the touchscreen to the bottom monitor:
xinput set-prop "Quanta OpticalTouchScreen" "Coordinate Transformation Matrix" 1 0 0 0 0.5 0.5 0 0 1

Before this command is executed, I can click by tapping the touchscreen and can drag itens or draw using the touchscreen without the mouse jumping to the bottom of the screen, but the position where X thinks I'm touching does not correspond to the actual position on the screen, since X thinks the touchscreen covers the entire desktop and not only the bottom monitor. After I run the xinput command, X interprets the touches at the right positions, but all those collateral effects take place.

However, the problems mentioned in items 1 to 5 in the beginning of the bug report (and many others mouse related problems) always happen, no matter xinput was ran or not. They go away if I install the package xserver-xorg-input-tslib, but then the touchscreen is disabled ("xinput list" then lists two touchscreen devices with the same name, but the touchscreen does not respond)

Is there any test I can do to provide more info that could help to solve this issue?