Comment 9 for bug 674346

@Jacob found the reason for this bug: update-manager in 10.04 uses synaptic as it's default backend (to install/update packages) but has now moved to aptdaemon as a default backend (don't know for sure whether it was for 10.10 or 11.04, I think 10.10 it was).
Jacob is also right that update-manager doesn't have a setting for that in it's settings panel (software-properties), and based on this investigtation this bug is about software-properties (update manager settings) not having a setting to delete packages after install/update, I am reassigning this bug to software-properties and updating the title and description with this information, and also subscribing Ayatana Design and mpt (the designer who has made the design for the update manager settings panel) to comment on the issue, and if required, update the design with the new option, or suggest any better ideas where the cleanup option should appear (as Computer Janitor is not part of the default install anymore, and it was not automatic anyway)