I noticed that the Android hardware buttons (menu, back, volume+, volume-) do not work when my Corona activity has focus. This occurs with my own project, a sample project, and the Corona fishies sample project.
Sometimes the hardware buttons work right after launching my app, but if i hit the home button then come back to the app, the hardware buttons no longer work.
This is a deal breaker because I have to allow users to use volume+, volume- and the back button.