Switching between multiple frames in Emacs is a pain when you have more than two frames open. I just noticed that the ace-window package offers the function for fast frame switching. All you need to do is to put the following configuration to the .emacs file and use the “M-o” key combination then pickup the frame number in red, and you will switch to that frame.
(global-set-key (kbd "M-o") 'ace-window)