I found plenty of web references by googling 'norton toolbar obscures'. If nothing else, they prove that you're not alone!
Reading through them though, it seems that the people at Norton were aware of the problem and theoretically fixed it with an update to the toolbar in 2015. However that's clearly not worked for you! Try removing the toolbar, closing Chrome, restarting your computer and reinstalling the toolbar:
To remove the toolbar, paste this line into Chrome's address bar:
chrome://chrome/extensions
Press Enter
You should see a list of all the extensions you've got
Click to remove the relevant tick
Click the trashcan icon
Close Chrome
To reinstall the toolbar, follow the instructions under Google Chrome here:
https://support.norton.com/sp/en/uk/home/current/solutions/v58055475_EndUserProfile_en_us