Help to eliminate the vertical line in replying to an email in iCloud on a Mac

I have searched for an answer to this without luck! Any help gratefully appreciated.

If I reply to an email, I get a blue vertical line the length of the received mail.

In subsequent strings the number of lines increases for each email, with text in different colours. With a message that has a number of vertical lines on the left side, I can't delete any of them to simply forward the email clean.

I don't use Apple mail, sending everything through iCloud via Google Chrome. I have looked at system preferences aswell as those for iCloud and Chrome without success. Previous posters have suggested unchecking the 'quote level' but I cannot find where to do this.

I have a Macbook Pro running 10.8.4. Thanks.