title: How can we make the hotkey function of an application always working even not in foreground
body: <p>Suppose I am running an application with several hotkey functions e.g. Ctrl+1,Ctrl+2,Ctrl+3
  However these hotkeys are only working when the application window is in foreground(i.e. on the top).
  How can I make the hotkeys still available even when I switch to other applications?</p>