Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I advise you to log out or Sign Out of the website (if you are signed in to that website.)
Then close all browser windows.
Then use Disk Cleanup to delete all
Temporary Internet Files
and then after that's done, open your browser again, bring up the website, and sign in to it with your account. Hopefully that will restore the left column properly.
(Also, if the browser window was full-screen before, and is not now full-screen, try putting it back to full-screen mode. Or, if it was not full-screen before and is full-screen now, try Restoring it to a partial-size window.)