1. A method of automatically creating a re-usable component for a user-interface, the method including: responsive to a user selection, automatically generating by a server of a shared on-demand database a re-usable component having access to one or more fields of the shared on-demand database based on a next unique identifier in a sequence of not yet used unique identifiers that are available and are valid for a specific client; wherein the re-usable component includes a code definition adopted from a pre-determined re-usable component template; presenting the re-usable component as an interface portion for display across an interface installed at and specific to a client; receiving from a user, customization code that modifies a functionality of the re-usable component; automatically generating an updated code definition of the re-usable component modified based on the customization code; creating a new re-usable component in accordance with the updated code definition; and presenting the new re-usable component in place of the re-usable component as the interface portion for display across the interface in a package received by and installed at a specific client; thereby enabling customizing the interface installed at and specific to the client with a re-usable component including the customization code used among a plurality of users in interfaces installed at and customized to respective ones of the plurality of users.