With some web clients (particularly Mac OS 10), mouse tracking does not work well. The fix is to disable mouse acceleration on the Linux computers:
- Configure the Linux windowing system to use Gnome (select gnome using the session menu on the login page)
 - Modify “.gconf/desktop/gnome/peripherals/mouse/%gconf.xml” in the user’s home directory
 - Search for “motion_acceleration” and change the float value to 1.0
 - Log out and back into to enable the changes
 
An alternative fix is to run
xset m 1 1
from the command line, or as part of your startup script.
To run the Avocent java-based console application on Mac OS X:
- Click on the console button on the web page
 - Save the kvm.cgi file to some location. Right click the file, select open with "/System/Library/CoreServices/Java Web Start.app", then choose always this as a standard option.