Chrome Version       : 53.0.2785.116
OS Version: 10.0
URLs (if applicable) :
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
     Safari 5:
  Firefox 4.x:
     IE 7/8/9:

What steps will reproduce the problem?
1. Load up some tabs
2. Leave Chrome window
3. Alt+tab / go back to Chrome window, to whichever tab was selected when you left
4. Click on another tab [AFTER YOU DO THIS, AN EVENT OF CHROME.WINDOWS.ONFOCUSEDCHANGED IS FIRED, which shouldn't happen since you are still focused on the same window]

What is the expected result?

chrome.windows.onFocusChanged should not fire when switching tabs (and usually doesn't - this bug is ONLY just after you've returned to chrome)

What happens instead of that?

chrome.windows.onFocusChanged fires (an event with window ID -1, The windowId value that represents the absence of a chrome browser window.)


Please provide any additional information below. Attach a screenshot if
possible.

UserAgentString: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36