chrome.windows.onFocusChanged.addListener not firing on tab switching

I am trying to fetch all events (maximized, maximize etc). I have a suitable code for this from this link How to Detect Window On Minimize/Maximize Event in Chrome Extension?.

But the problem when switch tab (using alt+tab) window.chrome.onFocusChanged listener is not firing.

My code :

chrome.windows.onFocusChanged.addListener(function(windowId) {
    console.log("focus change", windowId);    
});

Is there a solution for this or... it is a bug?