If you try to use the "." hotkey to access the quick nav menu when a control on the page has the focus, the "." keystroke will result in the control accepting the input instead of launching the quick nav menu popup.
You should always be able to hit ESC to cancel any control focus and ensure that your next keystroke of "." will activate the quick nav menu.
You should always be able to reach the quick nav menu popup without leaving the keyboard. That's the point of having hotkeys.