Unlocking the iPhone normally brings up whatever app was open when the sleep/wake button was pressed. Sometimes this is a problem, because whatever activity, video or music that was last displayed will still be opened upon unlock. Eclair gives jailbreakers more control over what appears when the device is first unlocked.
To improve privacy, Eclair can prevent the last used app from appearing at all. It works by hiding or terminating the app automatically when the device is locked. Once installed, there's a toggle to enable the tweak in Settings, along with some options to configure. Besides the option to hide or kill an open app after lock, Eclair is capable of always opening the SpringBoard home page at unlock.