The input manager autocompletion plugin is not installed on Mac OS X 10.5 and greater. Please encourage TeX front end developers to include this functionality. Details and code are available by contacting the BibDesk developers.
In the Completion pane you can configure the autocompletion system by installing citation autocompletion for external applications.
External autocompletion allows you to install a plugin which enables bibliography-item autocompletion in Mac OS X 10.3 and greater using the "Install" button.
When the plugin has been installed, the button title changes to "Reinstall" automatically. Autocompletion will only work in Cocoa applications, such as the ones in the picture, and they must be added to the list manually using the "Add" button below the list.
If an application you have added to the list behaves strangely after you add it, this is a clue that autocompletion is not compatible; Apple's Stickies application is a good example of this.
See section See section Autocompletion for details about how to use this feature once it is set up.