autocutsel (keep the X clipboard and the cutbuffer in sync)
Autocutsel tracks changes in the X server's cutbuffer and CLIPBOARD
selection. When the CLIPBOARD is changed, it updates the cutbuffer.
When the cutbuffer is changed, it owns the CLIPBOARD selection.
The cutbuffer and CLIPBOARD selection are always synchronized.
Autocutsel is mostly useful with window managers, since most desktop
environments today include their own clipboard managers. If you don't
use a display manager like KDM you can use autocutsel by adding an
entry to your $HOME/.xinitc file using the -fork option.
Some software (like OpenOffice Writer) has trouble when the PRIMARY
selection is requested before the mouse button is released. As a
workaround, you can run autocutsel with the "-buttonup" option and
it will only get the selection when the first mouse button is not
pressed.