I am using an Application Bar within my solution. I have tried using the Close method, but when I try to use TerminateRuntime it hangs. The only ways to stop it is to use the Gear>Exit on the Agile Desktop bar or to kill the process in task manager.
I tried to isolate the issue by creating a new blank project and only adding an application bar with a button the closes the application bar and terminates runtimes.
I am using SP1 8.0.2011 but it also exists in 8.0.2015.
Not using 8.0.2011 or above yet but are you using the following?
If you want to stop Runtime cleanly, in the Toolbox, on the Runtime tab, there is a static method you may add to an automation and call labeled "RuntimeHost.TerminateRuntime". This will trigger the shutdown of Runtime as if it were exited from the tray icon.