A colleague of mine and I uncovered an annoying bug in the Citrix Receiver for Linux 11.1 using dual mirrored monitors on Ubuntu 10.04 LTS. Basically launch a full screen desktop ICA session into a XenApp 6.0 server farm. Even at the login prompt for Windows 2008 R2 you'll notice if you click around with the mouse you'll notice the pointer and the mouse event occurs 3-4 inches to the right and in the same spot. I have already taken into account the Span parameter in WFICA and I tried updating the display drivers. If the desktop ICA session is set to only 95% of screen or if the 2nd monitor is removed the bug goes away. This only occurs with the Citrix linux client nothing else.
I solved it. I changed the refresh rate from 60 Hz to 75 Hz and the bug went away.