Abstract: Data structure and methods associating an arbitrary list of properties with user interface items on a graphical user interface display. Each property has a tag with which an application program can reference it, and arbitrary data which can be written, read and modified by the application program. Property lists for each user interface item are stored in in-memory pools of property lists. Each pool includes a header region having a variable number of index slots, each slot which is currently being used pointing to a respective property list in a property list region of the pool. Unused slots are maintained on a linked list of index slots. When a property list is to be added or removed from a pool, the maintenance routines grow or shrink the pool only by fixed increments. Each property list includes a variable number of property entries each having a tag field and a data field.

Abstract: Explicit support is provided at the system software level for application program tear-off menus in a manner that is essentially application-transparent. All menus are transformed into windows and grouped in a single menu layer for each application, greatly simplifying many of the complexities of navigating through hierarchical and tear-off menus. Each application has its own menu layer that is shown and hidden as the application moves to the foreground and background. Tear-off menus, as with all menus, are hidden and shown with the menu layer, generating the desirable "floating-window" behavior. More particularly, menus are managed in a graphical, event-driven computer system having a computer display by representing the menus as windows, providing a menu layer for containing menus of a computer program, and displaying a menu. Events occurring with respect to the menu layer are detected, in response to which display of the menu is varied.