I have been using VNC server on Solaris, and a viewer on Windows for a while and have been able to copy text from the VNC client to Windows easily. I have also been able to copy text from Windows to an Emacs *scratch* buffer, sometimes, but that’s about it. I recently started using VNC on a Linux workstation, and with this, I wasn’t able to copy in either direction.
I decided to research for a solution that would allow me to copy text both ways, and after some searching, I found some discussions where someone had suggested that running “vncconfig” on the Linux machine where the VNC server is running would enable copying both ways. I decided to give it a try, and typed “vncconfig.” It popped up an X-window where I could select a few options for VNC. I did not really change any of those. Then I tried copying from the VNC viewer running on Windows XP to another Windows application, and it worked!! I then tried copying from XP to the VNC viewer, and that works too!!