Pen registers on wrong monitor

[Rainman4500]

Hi,

I have a X61 tablet VISTA in a docking station with an external Dell 19Inch LCD monitor. If I touch the laptop screen with the PEN, it registers on the external LCD instead of the laptop screen.

I tried changing the primary monitor in Display settings but I still get the same behaviour. (except Start menu changes monitor of course)

My guess is monitor identification. External monitor is always 1 and laptop 2 when I press "Identify monitor".

Anybody can help?

Thanks

Stéphane