test case (requires no cached sudo-passwords): install openssh-server open a terminal execute "ssh -X localhost" login using your password execute "sudo synaptic &" execute "sudo synaptic &" again.
test case (requires no cached sudo-passwords):
install openssh-server
open a terminal
execute "ssh -X localhost"
login using your password
execute "sudo synaptic &"
execute "sudo synaptic &" again.