Prevent gnome-shell's dash from listing Recent Items
Gnome-shell uses recently-used and not Zeitgeist to display your recent items.
to disable it follow theses steps:
delete recently-used.xbel:
rm ~/.local/share/recently-used.xbel
create a new empty file:
touch ~/.local/share/recently-used.xbel
make sure the new file cannot be modified:
sudo chattr +i ~/.local/share/recently-used.xbel
now, your display of recent items is gone.
If you want to revert back, remove the i attribute of recently-used.xbel:
sudo chattr -i ~/.local/share/recently-used.xbel
all credits to : http://knezevblog.blogspot.com/2010/05/how-to-ubuntu-clear-and-disable-recent.html
There's also an extension Remove recent items search provider for removing the Recent Items provider now, as well.
Install " Activity Log Manager" using Synaptic and choose apps whose logs you wana see and whose not.