My cut and paste between my Windows 8 box and my RHEL box (running a VNC session) stopped working. After doing some reading (thanks to http://almost-a-technocrat.blogspot.com/2012/10/how-to-enable-copy-and-paste-between.html for assistance) I realised it's a simple answer:
In a terminal, run
# vncconfig &
And that's about it ... at least, it solved my copy & paste problems!