hide handheld footer bar when user is typing
Display area in handheld device is much smaller compared to desktop, and reduced further when user is typing because the device must show keyboard.
These becomes a problem particularly when user is typing on a dropdown list, or when searching using autofill. Some of the list/search suggestion will be blocked by the footer bar.
it is unlikely that user will tap on one of the handheld footer bar, so this bar is useless during this use case.