1. At least one computer-readable medium containing instructions which when executed by a computer, perform actions, comprising: at an interface, receiving an instruction to execute a command; in response thereto, attempting to find a command binding object associated with the command by traversing a hierarchical data structure; determining that a first, higher-level command binding object is associated with the command, the first higher-level command binding object including binding information that associates the command to a first instruction; determining that a second, lower-level command binding object is also associated with the command, the second lower-level command binding object including binding information that associates the command to a second, different instruction; and overriding the binding information of the first, higher-level command binding object with the binding information of the second, lower-level command binding object, such that the binding information of the second, lower-level command binding object is used.