rdesktop sends two mouse events vnc only one

I have Ubuntu 12.04 on a laptop with Logitech M570 wireless USB mouse. I connect to a Windows Server 2008 R2 machine using RDP. I have tried various GUIs and the best performance is from the rdesktop command line in fact the performance is very good.

However, the scrollwheel from the mouse sends two scrolls for each single scroll. During troubleshooting I installed TightVNC server on the Windows server and then connected using a few different VNC clients from the laptop. With VNC I got a single in the remote session.

I need to use rdesktop to get the correct resolution and improved performance but cannot identify what is causing the additional mouse scroll problem.

This is the only outstanding issue preventing me from removing Windows XP from this laptop and is proving very difficult to solve!

Thanks
Jason