WindowServer[250]: _CGXGLDisplayContextForDisplayDevice: No matching context for device (0x7fcfcaf18220) - disabling OpenGL
Add this to /etc/asl.conf and then kill -hup syslog:

# WindowServer messages about display context (caused by DisplayLink driver)
? [= Sender WindowServer] [= Level Warning] [A= Message _CGXGLDisplayContextForDisplayDevice] claim only


More about this here: http://www.displaylink.org/forum/showthread.php?t=62987&amp;page=4 



In case the explanation above is too cryptic:


Open Terminal
run SUDO_EDITOR=/usr/bin/nano sudo -e /etc/asl.conf
Use the arrow keys to scroll to the bottom of the file
Paste the text from above (the two lines starting with # and ?) into the Terminal window
Type Ctrl-X and confirm with Y
run sudo kill -hup syslog