Launchpad, the application launcher that Apple introduced with OS X Lion (10.7), was an attempt to bring a touch of iOS to the Mac operating system. Like iOS, Launchpad displays the applications installed on a Mac in a simple interface of app icons spread out across the Mac screen. Clicking on an app icon launches the application.

Launchpad displays app icons until it fills the screen, and then creates another page of icons that you can swipe open, just like in iOS. If you don’t have a gesture input device like the Magic Mouse or Magic Trackpad, or a built-in trackpad, you can still navigate between pages by clicking the page indicators at the bottom of the Launchpad.

All those icons on a blurry, semi-transparent background take a lot of graphical power to pull off. So instead of creating thumbnails of each app icon every time the app is launched or a page is turned, Launchpad maintains a database. It contains the app icons, their location in the file system, where they should be displayed in Launchpad, and other information Launchpad needs to do its job.

The worst thing that happens with Launchpad is that an icon for an app you deleted doesn’t go away, icons don’t stay on the page where you want them, or icons don’t retain the organization you created. Sometimes, when you create a folder of apps in Launchpad, the icons return to their original location the next time you open Launchpad.