I have a Google hosted mail account for my remodeling business. I signed up before they started charging people through the nose for the service so I am lucky enough to not have to pay for it. It allows me to check my email through a gmail interface and email people from my remodeling domain no matter where I am, it works great with my Droid phone, too. The problem is I also have a gmail account and with the roll out of Google+ I gained some great features, but I lost the ability to log into both of my accounts at the same time in the same browser. I was switching back and forth for about a week until I decided to run Chrome on another screen so I could see my remodeling email account as well as my gmail account (in Firefox). I’m not sure how this problem slipped by Google, but it did.
Well, it would appear they have finally fixed it after several months. Simply clicking on your email address in the upper right and then account settings you will see an option for “Multiple Sign Ins.” Select it and agree and you are good to go. You will have to do this for every account that comes through Google (ie.. multiple gmail accounts, or app accounts).
Hopefully this will help someone else out.