I know that this question has a very similar one but I just can't found the Application Switcher that Basharat Sial talked about. I install unity-tweak-tool but couldn't find there neither such option.
You need to install the extra plugins.
To do so, first, close CCSM. Then, open a terminal by Ctrl+Alt+T and type in the following:
When it's done, open CCSM and you'll find the Application Switcher under Windows Management.