Unfortunately I have set the mouse speed as fast as possible, with no acceleration as I prefer a more linear action when moving the mouse.
Even if I do enable acceleration, ArchiCAD seems to actually ignore it. When you switch back to the desktop or another application it is enabled again, weirdly!
I'm using a Logitech Cordless MouseMan Optical by the way.
One thing that may be a problem is that I am not using the most up to date logitech drivers (Control center 9.76.046, Mouse driver 9.76) as the newer drivers prevented the mapping of the 'escape' function to the thumb button which I find useful. So I will try updating these temporarily to see if they will help.
Thanks anyway,
Pete.