I read through wacom's driver bulletin and I think they address this issue. If I remember correctly a driver update caused this even when the right click mode was turned off. Newest driver is supposed to fix this heres a [link] Bulletin 091 to the driver bulletin. Thankfully it's pretty concise, so it's not a huge read.
This "Press and hold to right click" was seriously giving me the irrates as well.
To disable it in Vista:
1. Start Menu > All Programs > Tablet PC > Tablet PC Pen training. 2. In the Contents menu on the left click "For more information". 3. Customizing pen settings > Pen and Input Devices. 4. Under "Pen Actions" select "Press and Hold" then click on "Settings". 5. Untick "Enable press and hold for right clicking".
DONE! No more stupid annoying Vista loading circles when holding down your pen!