title: What's the difference between connecting signals and slot in code and setting them in QtCreator "Signals and Slots Editor" window?
body: <p>What's the difference between connecting signals and slot in your c++ code and setting them in QtCreator "Signals and Slots Editor" window?</p>
  
  <p>I saw in QtCreator window, there is also a "Signals and Slots Editor" widget and "Action editor" widget so that I can add  and edit. But when should I use it? Or I can just neglect it? Please tell me what is the best rule to follow. Thanks</p>