+ // this allows to choose whether we work with CLIPBOARD (default) or
+ // PRIMARY selection on X11-based systems
+ //
+ // on the other ones, working with primary selection does nothing: this
+ // allows to write code which sets the primary selection when something is
+ // selected without any ill effects (i.e. without overwriting the
+ // clipboard which would be wrong on the platforms without X11 PRIMARY)
+ virtual void UsePrimarySelection(bool usePrimary = false)