Some other users and i of the HP tc4400 TabletPC found that when plugged into AC electrical power, the mouse pointer would move to the bottom left of the screen.  Very Annoying.  One person from Japan noticed it only happened when plugged into a generic power AC adapter source.  Turns out for me it was the stylus, but it only occured when plugged-in.

1. Find the Numeric ID of the stylus as denoted by ID=

   1.     xinput list | grep -i stylus 

2. Using the ID NUMBER from the first step. Verify a bunch of numbers show up on the screen when the  pointer is moved with the stylus or when the stylus moves on its own:

   1. xinput test

   2. eg: xinput test 12

3. Disable the stylus.
   1. xinput disable
   2. xinput disable 12

Would like to detect when the TabletPC is on battery power and enable the Stylus.  Disable again automatically on AC power.  Most of the time, the stylus will only be used when mobile.