Flawed update. Downgraded for now. Very slow to load tabs  and switch between my site  reader and settings. Sometimes it just fails to respond and stays where it is. (All this on a good internet connection that loads everything well in another web browser app). It ultimately just refused to let me go back to 'view site'. Please fix. Reverted to v4.0  which doesn't look as nice but does the work.
April 28 2016