only 1 buffer for X clipboard

pacman -Si autocutsel :

Dépôt                 : community
Nom                   : autocutsel
Version               : 0.9.0-2
URL                   : http://lepton.fr/tools/autocutsel
Description           : synchronizes the two copy/paste buffers mainly used by X application

update your ~/.xinitrc with these lines :

Autocutsel() {
if [ -x /usr/bin/autocutsel ]; then
#this will keep the clipboard in sync
# with the primary buffer
autocutsel -selection CLIPBOARD -fork
fi
}
Autocutsel


or, put something like this in your window-manager :

autocutsel -fork
autocutsel -selection PRIMARY -fork