Gmail has introduced a new cleaner interface & it's been coming & going all morning.
I have my chat contacts on the right side of the screen & with this configuration the link to multiple accounts is missing.
Unless I'm blind & can't find it. :-)
It used to be your email address in the upper right.
Click on it & your option to open other accounts was there.
Now it's not there.
It's really annoying.
Am I missing something?