1. A computer executable method for use with a virtual application, a client application, and a host operating system executing on at least one computing device, the method comprising: executing, by the host operating system, a virtual runtime engine configured to generate a first user interface; executing, by the host operating system, the client application which displays a second user interface; executing the virtual application within a virtual runtime environment implemented by the virtual runtime engine, the virtual application being encapsulated from the host operating system by the virtual runtime environment; receiving, by the virtual runtime engine, a user interface message generated by the virtual application, the user interface message comprising instructions configured to modify the first user interface generated by the virtual runtime engine; instead of modifying the first user interface, generating, by the virtual runtime engine, at least one user interface command for the second user interface displayed by the client application, the at least one user interface command being generated based on the user interface message; and sending, by the virtual runtime engine, the at least one user interface command to the client application, the at least one user interface command being configured to cause the client application to modify the second user interface.