Also, on the panel that comes up when u activate the addon.. do you not see the "Toggle resize tooltip" button? Its a letter "i" over what looks like ruler measurements. 

Well, it actually does that now. Go to the settings, and under "tooltip" you have to turn on "Automatically show the resize tooltip on all pages". For me it then shows the window AND viewport size live as I resize the browser window.

What you said makes no sense.