Some embodiments are directed to controlling interactions between a host software program and a computer system by providing a managed execution environment running within the host software program. In one embodiment, a computer system integrates a managed execution environment within a host software program. The computer system uses the managed execution environment to interact with one or more features of the host software program. The managed execution environment includes interface controls configured to interface between the computer system and the host software program. The compute system alters one or more of the various software program features based on code that is identified in downloaded content.