1. A method performed on a computing device, the method for tracking testing of user interface elements of a user interface system, the method comprising: receiving, from a plurality of different applications running on a plurality of different computing devices, information associated with the user interface elements, where each of the user interface elements is identified by a global identifier that is unique across all of the user interface elements of a user interface system; storing the received information in a user interface inventory database, where a portion of the stored information regarding the each of the user interface elements is keyed on its respective global identifier, where the information stored in the user interface inventory database for the each of the user interface elements comprises scenario data that includes: metadata for the each of the user interface elements, time-stamped state of the each of the user interface elements, events associated with a change in the each of the user interface elements, and a sequence of user interactions with a sequential progression of a variety of the user interface elements of the user interface; and analyzing the scenario data, where the analyzing results in determining a measure of usage of the each of the user interface elements, a measure of testing thoroughness of the each of the user interface elements, and a measure of how often the each of the user interface elements performs as expected.