this is a good hack for xterm using it in gnome deskop (ubuntu, in my case)

I used to configure xterm, and it works!

Hi David,

It has taken me a while but your source helped me to find a softer
version for the Xterm Copy and Paste trick. (I used to compile your
program, but our sysadmin was not very happy about this due to obvious
updating issues.) So the patch lines helped me to find out that for
the Copy & Paste functionality one simply needs to add the
following line to the ~/.Xresources file:

XTerm*VT100.translations: #override : select-end(PRIMARY, CLIPBOARD, CUT_BUFFER0)

You can test it with an xterm:

xterm -xrm 'XTerm*VT100.translations: #override : select-end(PRIMARY, CLIPBOARD, CUT_BUFFER0)'

Maybe you want to add this hint to your page. I suppose there is a
certain number of people who use the hacked xterm source.

source

update: you can use also the package autocutsel to sync both clipboards