Previously, When I changed GOOGLE accounts on my Windows 7 PC's Chrome browser, a second instance of the browser would appear in the Taskbar.  I BELIEVE I changed accounts by clicking an icon to the right of the address bar.  That second instance of the browser would contain the bookmarks of the second account, and when I opened a new tab, that new tab would still be linked to the second account.

Then, I updated to Chrome Version 64.0.3282.186.  Now, when I try to change accounts, the behavior is completely different:  I no longer see that icon by the address bar.  I can apparently only change accounts by clicking on my photo, then clicking on "Sign out," then siginng into the second account.  However, once I do this, I STILL see the bookmarks of my FIRST account!  If I open another tab, it REVERTS to the first account.  If I open Settings, it shows me still logged into my first account.

So HOW can I completely and temporarily switch to my second account on the PC?!  Why in the world would I continue to see bookmarks, History, etc. from my first account, once I REQUESTED a change to another account?!  Can anyone tell me how to quickly and safely change Google accounts on my browser?